like a lot of other people I don't like the unique units in their current form. it ruins the unpredictability of the historic development of your civ and those of your rivals.

However it is unlikely that Firaxis wil remove it from the game since they have invested a lot in this idea.

My idea is to modify the use of these units so that they can be used in the game without annoying the players. For instance the first civ to discover bronze working will get the special Greek phalanx units, the other civ's that aquire the tech by their own research, theft, etc. will however only get the regular phalanx units (which are considerable weaker). This way countries which are in the spearhead of scientific progress (and probably are focused on development instead of conquest) will get a military advantage over the rest, which enables them to stand up against aggressors. The point is that when an aggressor aquires the tech through conquest or theft he still will be at a disadvantage so that he's more or less forced to focus more on doing his own research.

I highly doubt Firaxis will go for the "practical science" idea, because it complicates the economic model, and I'm sure they'll try to keep things simple and elegant.
Here's another way to fix the civ-specific unit problem. Option 1: people who want to play with special units the way Firaxis describes it, fine. Option 2: if you don't want them at all, turn them all off. In addition, have a third option, to work like this:

Each civ can only have one special unit. but none start out with any. If you are the first civ to reach a tech that gives a certain special unit, you can choose if you want the special unit that comes with it, or not. You might choose not, if you're angling for a different special unit that you like more. Eventually each civ ends up with one and only one special unit. The civ or civs that are far behind may not end up with their top priority special unit, though- a price for falling behind. Given that there's a max of 8 civs in a normal game, and 16 special units presumably, every civ should get a special unit that suits them, even if its not their number one choice.

So, for instance, if you're on an island, you might beeline for the Longship. If you're a land based civ, you might beeline for the Horse Archer (imagining the game has a Mongol specific special unit). But if you don't plan on going to war in the middle ages, you hold off and aim for the Panzer later on. And so on. This makes a lot more sense than say, the Germans have an inherent ability to build better tanks, a destiny foretold thousands of years in advance, even if they're in a situation where Panzers are useless.

With this option, there would be all kinds of fun strategy. Do you go for an early special unit and shoot your wad early, or go for a later one, when maybe you won't even last that long? If you're slightly ahead of a competitor, do you take a special unit just to deny it to them? It would be kind of like having an ace in the hole, ready to be pulled out when needed the most. It also means that the civ that gets the special unit was really the one or ones that excelled the best in that technology. It makes military players have to excell in science much more than when you have a predetermined special unit. It might even help a player that's fallen behind catch up, cos it would be likely the technological leaders would pick special units early on, leaving the player that's fallen behind some great late game units. The possibilities are so much more interesting than having the situation fixed.

As to LoA's objection, I don't think that really applies. Since there are 16 possible special units (one assumes), and a max of 8 (or 7?) civs, everyone should get a good pick. Hopefully one can increase the max number of civs in one game, but then also it should be possible to increase the total number of civs to choose from, so it should balance out.