Meta Group Designer?
I'm coming off a recent GalCiv III binge and had a thought on meta groups.
Have you thought about putting a "meta group designer" into players' hands? Kind of like the ship builder in Gal Civ III, but a much more basic interface used that could be sued to create custom Meta Groups and related build lists (e.g., not to change the appearance of the units or anything). Something akin to the fleet builder in Gratuitous Space Battles that would tell you how much metal you'd need, how many reactives, etc.
The way I see it in my head is that players could play around offline with assembling meta groups of various unit combinations, see what the buffs would be, and then set the group. In-game you could build your factories and then task one or more with building Meta Group 1, Meta Group 2, Meta Group 3, etc.. Once you set the build orders the factories would pump out your pre-selected units in the numbers you've specified. This does not seem like it would require much AI horsepower, but it would let players customize their builds, focus on more strategic issues than unit building, and maybe make me care more about building a bunch of metal/reactive storehouses everywhere so that I could build up resources during a game to make my killer Meta Group build #5 or w/e.
This approach would also add a new level of strategy to the game and give people something to play around with offline. My sense is that a lot of strategy would go into optimal builds, since you must weigh in-game manufacturing times, the resources on a particular map, buffs, etc. People might even customize their builds to specific maps based on the resources available and/or their opponent.
Just something I thought I'd toss into the ether.