I think we'll have to agree to disagree there. While I share your concern, I'm just not seeing the need to turn-by-turn calculate what the AI would do. If the player isn't there, it doesn't need to be scrupulously fair - so a few shortcuts will do.
I'm not seeing that there would need to be a turn-by-turn calculation of what the AI would do. It would be too impractical. I think what would need to be done is to have a civilization generator that can generate civs intelligently based on surroundings and maybe some other factors.
As to the stale experience, real turn-by-turn AI would take over as soon as the map is done expanding - and unless you've got some spell which reveals the whole map you aren't going to see anything "stale" or "cookie-cutter". You wont see anything but blacked-out areas to explore, and while you're getting there the full-on AI will do whatever it does with points of interest and developing the map.
I disagree. Hopefully there will be a lot of strategy involved in city development. It seems to me that making a civ generator capable of creating completely different, yet functional civilizations would be difficult. Even though the player likely won't interact heavily with the AI immediately, if every time you expand the map the game creates similar civs to fill the world, the player will still notice the similarities even long after the AI has taken over.
And, your point about the full-on AI doing whatever it does with points of interest and developing the map while you're still getting there would just put the new civs at disadvantages. It would put the AIs hundreds of turns behind the player in that aspect.
MoM generated plenty of cities at the start of the game - handing something a little more complex than that over to turn-by-turn AI would surely be enough. Really only one way to find out though... an alpha test
Generating individual cities would be relatively easy. Generating a civilization consisting of multiple cities that make strategic sense, plus relevant standing armies, etc, seems like it would be a whole new level of complexity.
I still really like this idea, but if the civ generator isn't sophisticated enough to create a different experience each time then I don't think I'd find myself using it very often. On the flip side if it's done extremely well I would probably almost always start games on smaller maps and then choose to expand it on victory.