1. Treaty Making
I think that when in the peace-making process, we should be able to make certain demands for a treaty rather than just hoping they offer us some money. And we should be able to refuse any counter-proposal they make.

2. Mediation
Okay, a loyal ally is being attacked by a much larger civilization. You cannot fight this opponent yet, and if he defeats your ally, he will be vastly more powerful. Or worse, a war that you have no interest in but it involves nuclear weapons. This could turn your continent into a wasteland. What do you do?

Call a meeting between the warring civs. Settle it. Request a peace treaty to be signed. If they refuse, get them to make concessions for peace. Make them agree to a non-nuclear pact or something.

3. A proper introduction...
Wanna set the fuse but not hang around for the explosion? Introduce your friends to other civilizations they haven't come in contact with yet. Hopefully, they'll spend plenty of time attacking each other and very little attacking you. Or be introduced by your friend so that you can send a nice "welcoming" party to his buddy's capital city.

4. Yalta: Gathering of the Allies
Want to gather all of your friends together? Call a meeting of the allies. Use this time to exchange technologies mutually, distribute weapons, give funds, and lay claim to cities. Or in peace time, set ecological pacts, discuss joint declarations of war, and technology sharing.

5. Allied Victory
Hate it when those AI allies of yours don't know an attack strategy from a hole in the ground? Take command of their attack forces! Request control of their troops and destroy your enemies. They get to keep the cities their troops take, and you get to weaken your enemy.

6. Good ol' U.N.
Don't want just a wonder? Here's an official organization of countries. They hold a council of all the civilizations. They mediate peace treaties and ecological situations.

7. $&%! Peace!
Tired of amassing an invasion force only to be delayed waiting for permission to use force but you don't want to tarnish your good name? Just declare war on your enemy instead. Don't wait until he is aggravated enough to do it himself!

8. Miscellaneous...
How about an AI thats aware of its own mortality?
Whats with the threats from the puny civs?
I'd like to demand cities and land from my AI enemies.
Allow acts of war that won't automatically cause a state of war to occur.

Ok, thats good for now....