3. Diplomacy

Via the diplomatic screen, you can sign several trade treaties and agreements. The first thing is the creation of trade pacts, or alliances, between three or more nations. In this trade alliance, you all automatically trade between you (with a nice big bonus). Also, all of the below treaties suggested are done with a bigger profit and efficiency then before. Active trade improve the relations between two nations. The more treaties you sign, the better the level of diplomatic relations will exist between the two nations. The suggested treaties have been posted on the various threads:

3.1) Single trade: exchange cities/tech/units/money/resources/land between two nations.
3.2) Fixed trade/tribute treaty: exchange/give money/food/resources every turn until canceled.
3.3) Construction: side A pays side B to build for him X units.
3.4) Shared wonder: both sides build a wonder togther (cheap in a labor/money pool), and get the effects togther (all possible in wonders that affect the entire civ, not just a single city).
3.5) Hired workers: side A pays side B for an agreed labor level (moves from side B city to side A city).
3,6 Monopoly: side A may demand side B to only buy his commodities only from him.
3.7) Lending money to a section side.
3.8) Port contract: side A pays side B to buy (or build) a port/airport on his land.
3.9) Trade passage: side A allows side B to pass caravans (or trade with nations only his is connected with), but gets a cut of the profit from the trade.
3.10) Embargo: side A demands side B to cancel all trade with side C.
3.11) Funded trade: side A pays side B to establish a trade route with a new nation (buying caravans, etc). They split the profit.

4. War and peace

The diplomatic relations between two nations should give you some specific bonus/minus. A state of war should give a boost to military production, but should drain civilian resources for a prolonged war. This could be viewed at increased support cost for units after long periods out of the city, increasing the minus to production in the SE screen, or simply reducing the bulk income. Unity, a high form of alliance, vastly increases trade profit, but makes you more vulnerable to spies.

5. Free-mind companies

5.1) Companies, and free trade, should hold a much bigger and obvious power in the game. Dictates by your market option, some of your economy (all, part, or none) should belong to private companies. You will stay gain the credits (via tax). It's more to show a real-life view and increase the realism of the game. The company could be a corporation (in transnational), a bank, a guild, a labor union, a single merchant, or a group of merchants. The type (and size/limitation/behavior) of the company depends, as said before, on your market option. The companies control parts (or all) of your caravans (or trade routes), and use those credits. They will build their own caravans. If in their interest, they will even build buildings in your cities (such as market places). But the profit from those will only go to the company: you only get a share via taxes. They could even build wonders if it will be profitable for them! The company will also build ports and airports, and roads/railroads to expand their trade sphere. You can sign construction treaties with companies, and cast "Embargo" and "Monopoly" treaties. You can also have "food" companies that will own part of your farmers and farms. They will even produce more food then you can (per tile), and give you a part of the profits. If needed, they themselves will build their privately owned farms, granaries, food markets, etc.
Switching market option from one with companies to one without (for example, from transnational to planned), will cause several things: all company building and units are moved to your hands, and you gain the full profit from those, but you will receive a large minus to all economy for several turns.

5.2) People have expressed wishes to be able to actually "play" for themselves the "free-mind" companies. You should have the option either to "zoom in" and take control of one of your nation’s companies for several turns, or to start the game as a company and play it over along the game. (One player can build the empire, and his friend managing the company at the same time, at multi-player. Maybe even several players playing several companies with a single player, or multiple civ players. A possible future add-on?) In addition, some suggested the option to play the pirates (see idea 1), and play them!

5.3) Beyond companies, you should the more "generic" private sector. The doing of the private sector are completely autonomous and unknown to you (not hidden, just not reported). As a general thing, the private sector will deal with building his own key city improvements alone. Like libraries, churches, market places. Those will be built by the public expense, not the government. The extent of power the private sector posse relies on your SE choices in government, market and structure. If Budgeting would be used (see idea 2), then some of the cost will be collected from the appropriate branch. For example, the government will finance some of the cost of building new churches out of the religious section in the royal budgets. The maintenance cost will also partly drop on the shoulders of the government.

5.4) Once transnational market option has been discovered by any nation, the central banks are created. It's yet another AI company that you may converse and sign several treaties with. The world global bank will invest in civ, buy off city improvements, lend money, and if holding enough power might even posses a small army of it's own (for the sake of guarding the economical stability, of course). Or maybe it could be created when a specific wonder has been created?

6. Trade-model options

6.1) Considering how faulty the trade system was in civ II, a new system must be used. Trade was very ignored on civ II, and no one can deny the absolute great importance of trade along history. This section list all of the new trade methods proposed:

6.1.1) Use the caravan system in civ II (in this case, make sure you use some modification to the system, see idea 7).
6.1.2) Internal trade is automatically, like SMAC. All cities generate a small trade bonus, regarding the size of the city, size of the empire, location of cities and eco bonus. External trade is done with caravans (see idea 7 to further increase this).
6.1.3) All trade is totally automatic, just like SMAC. The income generated also relies on the size of your allies and their numbers.
6.1.4) All trade income is generated by signing "commerce treaties,” like Master of Orion series. It is signed via the diplomacy screen, and generates a fixed amount of cash every turn. The size of profit depends on the population size of the two nations and any commerce bonus/penalty either of you have. The size of the profit is negative at the start, and is increasing steadily over time.
6.1.5) Every big city can support several trade routes. The number of routes is decided by your SE options, tech level and city size. Each route is connected to a city of a non-hostile nation. Every foreign city can be connected to just one cities in your civ.
6.1.6) Trade is done with buildings, not units at all. You build a "depot" in your city. You automatically gain a profit, considering how many cities you have near you, the size of your city and the size of the city you are connected with. The size of the city decides the maximum bonus you can get, and how many other cities can gain bonuses from this city. For example, if a foreign nation has a city which can support three connections, it gains up to three connection bonuses, and only three other cities can get a bonus from her.
6.1.7) Just like 6.1.5, your city gain trade routes. However, when you create a trade route it will automatically call for the nearest available caravan and send it to create the trade route.
6.1.8) (Requires a commodity system) Trade won't generally produce any credit: no tiles producing trade arrows. Nations only trade resource/commodities between themselves. The majority of profit would be, ofcourse, to buy cheap and sell high ( usally being a third side between two nations ). The value of each commodity vary upon supply and demand. However, every trade gives both sides a few credits upon completion of the trade contract. The bigger the trade is, the more profit both sides will get. Another option is when a trade agreement has been made an available caravan automatically is sent to the other nation land.

6.2. Civ II didn't allow you to trade with barbarians: a very false idea. Barbarians should have a bigger role: like pirates they could have some diverse options, and can also build cities, if they obtain the cash to buy a settler. In a nutshell, people would really like the option to trade with barbarians, primitive and nomadic tribes.

6.3) The economy, and income from trade, needs to shift up and down, like in real life economics. The more free your society is (democracy/free market), the more the numbers will shift for better or for worse. In social or controlled markets however, the market will hardly shift at all. Shifting can cause up to +/- 50% of income in a single turn, and move up or down by an additional -/+ 5% every turn.

7. All about caravans

7.1) If the caravan system will still be used (see idea 7) some modification to the system needs to be made. The micro-management of each caravan in civ II made trade so very bothersome, that some players choose to ignore it completely. The caravan system could be changed to the following:

7.1.1) Keep it like civ II: you build them, move them around and create trade routes (which a creation bonus when first creating the path).
7.1.2. You build the caravans yourselves, but they automatically move to the most profitable location (decided by distance, ETA, merchandise carrying, nationality of the city, etc.). To increase procession speed, you could make the caravan invisible (totally automatic).
7.1.3) Caravans are generated automatically at large cities (depending on city size and location, like rivers and coastal connection). They are replaced after X turns if they are killed. You then direct them to their destination.
7.1.4. A trade advisor governs all trade for you: he builds the caravans, moves them about, and chooses the best merchandise for maximum profit. You also can toggle "caravan viewing" for extra speed: without seeing the caravans the game will run faster. He will also manage building roads and ports for you. The advisor could be mandatory, or could be optional, and be switched off/on.

7.2) To further increase the depth of the caravan system, new caravan types were suggested. Those specific-task units will further enhance the depth of trade. They will can be used with automatic trade (trade advisor). He would build armored convoys when sending them into "hot-regions,” use "double-capacity,” or "finished goods,” if it's more profitable, etc.

7.2.1) Special movement: a trade plane and ships. Trade ships are critical for realism.
7.2.2) Double capacity: costlier, slower caravans, that carry a double cargo that offers a bigger income.
7.2.3) Armored convoy: a costlier caravan that has some defensive capacity and can protect himself for pirates.
7.2.4) Finished goods: a costlier caravan version, but one that offers a much bigger profit.
7.2.5) Tourist caravan: carry no resource. The profit is purely set on the size of the two cities, with no connection to request and demand. Losing a tourist caravan, however, causes grave diplomatic strains and morale drops.

7.3) New ways to get caravans: hire them! Hiring caravans can come at two options. One, is hiring privateers. Privateers are controlled by the AI, and automatically seek the most profitable location. Hiring privateers reduce the time and cost to takes you to make a new caravan: but you only get a cut from the profit, and you can't control or direct your units. Full hired caravans are under your control, just like any unit. You don't build them however, or buy them: you rent them for a fixed price. Like privateers, you don't get the full cut of the profit from the trade route.

7.4) Convoys may help a besieged city (under artillery fire, or an enemy unit is in the city radii, or both). If armored convoys exist, only they may do it. If not, then any sort of caravans. Helping caravans generate food for the helped nation, and reduce money (at a reduced cost) for the owner of the caravan. However, it will greatly boost the diplomatic relations.

7.5) Caravans can assist cities that were harmed by a random event (earthquakes, tornados, etc.). The caravan helps fix the damage to the infrastructure and boosts the food supply for several turns. You gain no money by this interaction, but you do greatly help the diplomatic relations between the two nations.

7.6) Caravans can't simply "help" wonders. They only reduce the mineral cost of the wonder, not increase the labor rating (by offering new means of construction and rare items). If the caravan is carrying construction goods (timber, concrete, steel, etc.), the bonus to resource is doubled.

7.7) Caravans "know" how to use boats, and will "call" for one automatically when it needs to pass over the seas. In other case, a caravan unit can be "glued" to a ship which will move the caravan all the time. In yet another option, you can set ships into "trade mode,” where those ships, and only those ships, will be "called" by the caravans to move them back and forth.

7.8) Instead of having caravans create trade route, caravans move back and forth. Instead of generating a fixed amount every turn, the caravan will produce a sum of money whenever it reaches another city on the route.

8. Trade routes

Trade routes are the path where trade passes between cities or nations. It could be caravans moving back and forth, or a generic "trade route" which is generated automatically. The following things can be added into trade routes to make them more realistic:

8.1) Once you create trade routes with another nation, you can't cancel it alone. Your only option is to cancel all trade with that nation, which means breaking ALL trade routes and all profit gotten from them.

8.2) Once you create a trade route (with a caravan or not), then you can further expand the level of trade that pass by the path automatically, by signing extra "contracts" that can further increase the profit and resource swapping that go along the path.

8.3) Trade routes can never pass over enemy land, or any nation that didn't sign a "right of passage" treaty with you (or you are in a high state of alliance with them). The route will go around the land, and it's impossible, the trade route will be canceled.
8.4) You should be allowed to toggle "economy map,” and view all the trade routes displayed over the land, with statistics over the city names showing the level of profit.

8.5) A city that sits on a river or on a shore (or both) gets an extra trade route credit (or extra income from trade, if that system is not used).

8.6) Trade routes automatically adapt themselves over roads/rail roads over ground, and into the "trade winds" along the ocean (fixed paths in which movement cost is ½ ).

8.7) All tiles that belong to a highly active (several caravans using it), trade route generate +1 trade ( considering you use the X10 format, see idea 14.4 ). All cities that have trade routes pass through their radii benefit from the trade route in this manner. This is cumulative: if several trade routes pass by the same tile, then that tile can get a larger bonus. However, the tile is last to receive this bonus (see below). However, the maximum income that can be gained (the number of tiles that get the +1 bonus), depends on the number of caravans, their profit, and their type. Important! A land trade routes that link two of your own cities (a domestic trade route), would get no such bonus at all. It has to be linked to another nation city.
For every land caravan, you gain up to half the profit they generate. Boats give ¼, and planes nothing. For example, a land route with 2 caravan that each generates 20 trade icons per turn, can give up to 20 tiles a +1 bonus. If they were sea crafts, the bonus would have applied to 10. If one caravan is land, and the other is airborne, the profit will be 10 since airplanes generate nothing.
This bonus is received by all friendly nations of the trade route owner: not just him.
If the number of tiles is smaller then the bonus (a 50 tiles trade route with only a bonus to 10), then only those that belong to a city would get the bonus. After that, railroad tiles are last to get a bonus, since when a train speed past a city it's less likely to give any profit. If still in need, large cities collect the bonus before smaller ones. Therefor, in order of importance, this is the tiles that get the bonus:

City tile (center)
Village (see idea 11.3, on the village itself)
Inside large city radii + road/river
Inside large city radii
Inside large city radii + railroad
Inside small city radii + road/river
Inside small city radii
Inside small city radii + railroad
A city tile that already has a bonus (for extra, cumulative bonus from several trade routes)
Outside city radii (doesn't really matter, does it? Since no one does get it anyway...)

8.8) If a trade routes pass over a road, and several caravans move on the road, it is automatically upgraded into "Royal highway," which will give a slightly better increase in speed (1/4 instead of 1/3).

8.9) If you create a trade route between two of your nations over sea, you can assign a transport ship to the trade route. That ship will automatically ferry units from one side to the other. Your units (caravans or any other unit) that were directed over seas will automatically move to the harbor on their side and wait for the ferry. Several ships can be assigned this way to the trade route.

8.10) Trade routes can use accepted way points.

8.11) You may position a military unit along a trade route and order it to "raid" it, diverting all income to you. Consider a hostile act. Pirates (see idea 1), use it all the time to generate more cash. Spies can destroy the trade route totally.
8.12) Trade route profit relays only of supply and demand of both the cities in the trade route. The bonus for distance (like in civ I/II), is better represented by the +1 trade per tile idea (see idea 8.7).

8.13) Trade routes take a small amount of cash to maintain. The cost is decided by the route length.

9. Inertial trade

Inertial trade is a radical idea that states that you can "center" your nationwide trade power on several cities. For example, frontier cities always support the bulk, if not all, the trade routes (caravans, automatic, whatever the system is). In inertial trade, you can transfer the "option" for trade routes to a nearby city. So, a single city could get 5,10,15 extra trade routes when several inner land cities pass their "Trade power" to her. Of course, for play-balancing, there is some lost which increase the more trade routes you pass. You can pass 1-2 with no loss, but try to pass 20 and you only get an extra, let’s say 10, for the destination city. This represents trade cities that dealt with trade for most of the empires. With contracts, you can even grant the other nation trade routes credit for him to you (when you are getting some back, of course).

10. Tile improvements

10.1) The current system used to create tile improvements (such as farms, roads, etc.) is very bulky and require a great deal of micro-management.

10.1.1) ]Keep the current system (settlers), but further develop the automation option that was introduced in SMAC.
10.1.2) Use the public work option like in CTP: you earn work points, which you can spend to construct public works.
10.1.3) Combine public works with settlers: build them in the public work menu, which will automatically send a settler to construct them (for the public work points), automatically.
10.1.4) If companies or private sectors are used (see idea 5), then many tile improvements will pop up with the support of the public himself (farms and roads, mainly). If budgeting is used (see idea 2), then increasing the development section will make more tiles produce themselves. You can also hire the company to build tiles for you.

10.2) Regardless of what system, tiles should cost maintenance, mainly the roads and railroads. Roads that are not properly maintained decay over time. If not using budgeting (idea 2) to support tile improvements, they could cost gold, or just degrade if not used for some times, requiring a settler to fix it (takes half the time). Roads that are not traveled, mines that are left alone, farms that are not tilled, etc.

11. Trade buildings & wonders

11.1) To further show and increase the importance of trade, you should have several buildings, and even wonders, that increase the usefulness of trade. The effects of those buildings/wonders can be:

11.1.1) city can support extra trade routes (one or more). Wonder can give an extra trade route for all your cities, world wide.
11.1.2) Extra profit from trade routes: a fixed amount of an added percentile.
11.1.3) Free caravans upon completion of structure. A building can give you an instant caravan for the city, and a wonder can give you one free caravan in every city you have. Another option is a wonder that generates a free caravan every few turns.
11.1.4) Reduce the number of population you need to support one extra caravan (see idea 7.1.3 ). For example, instead of a caravan every 5 pop, you get one every 4. Local effects for buildings, world wide effects for wonders.
11.1.5) Increase movement of all caravans (wonder only).
11.1.6) Reduce support cost of all caravans (wonder only).
11.1.7) Increase carrying capacity of all caravans (wonder only).

11.2) Settlers can build a new type of building in the outlands: a trade depot. The trade depot can do one, some, or all of the following options:

11.2.1) Give a bonus to trade in the range of operation.
11.2.2) Act like a fortress.
11.2.3) Heal all caravans resting one turn on it.
11.2.4) Building, or generating caravans.
11.2.5) Defend all caravans in range of operations from raiding.
11.2.6) Resupply all fueled units.
11.2.7) Store cargo.
11.2.8) Act like a waypoint: you can send units to it by the command "go to.”

Sea ports are built on shore tiles, and act just like a trade depot: only they work on ships (protecting/building/repairing ships). You can also ask via the diplomacy screen for your friend to build a port/trade depot for you (see idea 3).

11.3) Villages are constructed by a settler, which forces the settler to disband (like building a city). Villages are a bit like supply crawlers from SMAC: they generate some food/resources which they send to the home city (the original city of the settler). If that city is destroyed, the bonus can be directed to any city of your choice. You can't build a village with your first settler: only after you have at least one city. While a village is in fact a one pop unit city, the pop unit does not count toward your city total (it does however on your nation scale), and requires no food. They are several types of villages:

11.3.1) Farm village: produce food + resources + trade in equivalent of the tile the village sits upon. The tile automatically has food improvement on it (irrigation, fields, farms, farmland). Must be built on flat, fertile land.
11.3.2) Mine village: Just like 11.3.1 in all cases, except you have a mine on the tile, and must be built on a mountain/hill.
11.3.3) Fishing villages: Only produce food and trade (no resources), but you automatically generate food like you are using a fish-improved ocean tile. Must be built on a shore.

12. Effects of trade

While one nation trades with the other one, they affect each other. Specific events can also boost, or hamper the profit generated from trade. The suggested effects of trade are:

12.1) The most basic one: the more trade you generate, the better the diplomatic relations between your nations.

12.2) Trade slowly generates a map of foreign territory: the area around the cities you trade with, and all cities that are interlinked via trade routes with those cities.

12.3) If one side possesses some technology the other one hasn't, the other side can easily acquire it (less research points needed).

12.4) If one side possesses trade tech and the other size doesn't, after one single trade the other side acquires it too.

12.5) The side that posses a clear technological advantage gets a bonus to trade.
12.6) Trade in general greatly increases technology output (more scientific relations, diverse cultures originate more ideas, etc.). Maybe make trade routes produce a small science bonus?

12.7) Cities with large population and food production obtain a small trade bonus: cuisine is a key industry in trade and tourism.

13. ICS solutions

The problem of ICS, meaning one city size, has been discussed heavily over the forums. Mainly, the problem relies on the fact that small cities, usually one pop size, are more profitable then large cities, making it unprofitable to spend money on expanding, beyond hampering realism. One, or a few, of the following solutions could be used:

13.1) Increasing the production ratio of workers at a geometrical rate. For example, the first pop gives 10 labor, second 20, third 30, etc. So, a 3 pop size city would produce 60 labor, instead of 30. This is fitting to the fact that the level of population in real numbers also increases geometrically. If this incremental increase seems to steep, maybe 10-15-20-25 system is better used. Like the above idea except increasing trade profit. 1 pop city produce 10 trade, 2 pop city produce 30, etc, etc, etc...

13.2) The city center tile won't produce anything, just give a +1 food/+1 prod/+1 trade to all surrounding hexes.

13.3) The effects of specialists (which are usually only used on large cities) should be much bigger.

13.4) You can put several workers on the same tile, but it with reduced efficiency (up to a max of 3 workers per tile). This will allow big cities to put more people to work, and further increase their power.

13.5) The number of population that can be put on tiles is city size -1. Meaning, a size 1 city would just work on the city center tile production, size 2 city would only have 1 worker, not 2, etc.

13.6) The maximum number of production increasing buildings that can be built is the size of the population. So, a size 1 city could only support 1 market/factory/bank, making bigger cities more profitable.

13.7) World-wide wonders that give "+1 happy citizen per city" unbalance things in favor or the smaller nations. Maybe it could be replaced by "+10% happy citizens in city".

14. City management

This section list all of the changes suggested to the "building" menu in cities, to further increase the ease of control of the player over his empire.

14.1) Having build queue: up to 5 buildings, one after another.

14.2) Allow multiple construction at the same time: slider bars share the labor power between various constructions. The maximum amount of items that can be constructed at the same time is either fixed (4-5?), or decided by your city size/tech level/city improvements. One idea is simply to have city improvement construction separate from unit construction.

14.3) Making the governor more intelligent, and allow worldwide control over governor (and regions). Also, allow more fine-controlling the governor.

14.4) All production values related to cities should be increased by a factor of 10. Meaning, a farmer produces 20 food instead of 2, and every citizen consumes 20 food instead of 2. By increasing the numbers, you allow small increments to be used (+10% to food, for example, almost never has any effect in the current system).

14.5) The population logarithmic scale used in civ II isn't very realistic. For starters, 10 thousand citizens for a starting village/hamlet, mainly in the old days, is way too much. One thousand sounds more reasonable. On the other extreme, even the largest cities never tend to reach the size of truly huge cities on modern Earth. Fixing the scale is very needed.

14.6) Instead of using pop size units in a logarithmic scale, use real-life numbers. You then divide the citizens by percentile among the works (for example, a city has 120,000 people, and 12.1% are working in farming, meaning food production per farmer * 14520).

14.7) Totally change the way you manage your cities and workers. You build generic buildings like farms, factories, libraries. You then assign work force (the size of your city) to the various building in a sort of a slider bar menu. You can then upgrade the buildings as technology increase. The basic output of farms and mines is decided by the surround lands around the city. This system was introduced in Birth of the federation. It's far more realistic: farmers should hardly give any labor or mine output.

14.8) Trade goods should be a conversion of minerals to goods (by labor) and sold automatically for profit

14.9) Citizens can either be assigned in tiles, which produce food + resources, on inside the city, which produce labor. One labor + one resource equals one civ I/II build shield. The concept of labor is based by many of the ideas included in the summary. However, it means starting cities would need several workers (since one would not be able to both mine and build). Another option is that all workers tend tiles, and automatically produce X amount of labor (in this case, make sure you see idea 13.1).

14.10) When building military units, and if your social options allow (free market), you may hire them as mercenaries. They require no construction or buying, and they start as veteran, but they cost twice as much to support and are less loyal to you (easier to bribe them). Another, more realistic option, that you can't just hire any unit, you have a few offers that will vary along the time.

14.11) Since shipping items from the fringes of the city in early days was very hard, the outer ring of the city radius has a "maximum output" setting that will improve along the years when new city improvements are allowed. For example, a farm can produce 5 food, but since it's the outer fringe it can only produce 3 (the rest are lost). Build a warehouse, and it will increase to 4. A highway will raise it once more to 5. Tiles that are connected by road have a +1 to their maxima. Connection by river or railroad gets +2.

14.12) "Rush-buying,” meaning buying the rest of the product in a city in a single turn must be limited due to vast un realism. In a resource system, you can only buy the resources and still need to build them by labor. In civ II old system, limiting the buying to only doubling the speed would do it (produce twice as fast, and buy the difference in shield * 2 every turn).

14.13) Citizens that are not assigned into any tile, and have not been yet "specialized,” are considered "unemployed" and increase the city unhappiness. Certain key technologies would increase unemployment for a few turns (like Industrialization, robotics, and other economy-changing techs).

14.14) Lack of communication for a long period of time can result in a city breaking down and declaring independence. The further away the city is, the more likely the city will revolt. The following things can decrease the chance: soldier inside the city, trade route connection with your empire, roads that are connected (by some way) to your capital, key buildings and wonders (like torch-lines), and technologies (radio, TV, etc).

15. Regions

The concept of regions is that you are able to "group" several close cities into one shared pool. The number of cities in the region, and its maximum size depend on your SE options and your technological level. All the "grouped" cities pool their food, resources and labor rating. The food pool first take care of the need of all the cities: any surpluses are shared equally by all cities to produce pop growth. The "home" city, either selected or the biggest one, is affecting all the others. All wonders that exist on this city, or buildings, give their effects to ALL cities in
the group. A temple, for example, would reduce 1 unhappy drone in every city, not just his hometown. A wonder that normally affects the hometown will affect all the grouped ones. However, buildings that only exist in the other cities won't affect ANY city, including the one with the buildings. Wonders that only effect the home city, and exist in another city than the central one, won't give a bonus to ANY city. However, the support cost of all buildings/wonders in the center city is doubled by the square root of the number of cities. For example, a temple in a 9 city pool would cost 3 times more, while affecting all the cities. Once the grouping is canceled, the support cost returns to normal.
For limiting the power of regions, it was suggested that only a specific set of buildings give an effect to all cities (like highways, or stock exchange), and the other needs to be built several times (maybe a nice menu that tells you the number of temples you have, and how many cities you support). Maybe the buildings that don't affect all the cities generate a bonus regarding on the comparison of amount/city size. For example, if you have 10 cities and 5 temples, maybe all cities will get a temple bonus, but only 50% of it (5/10). Extra! Another way to implement this is by creating "regional command" in the home city. Since "Grouping" can be very powerful, the support cost for the command building should be very big.

Posters: