I don't diagree that you empires culture greatly affects many aspects of it's development, even technology. I was thinking along the lines that sinec these empires are all made up of men, they just shouldn't have any prediliction towards one or the other until the game starts. That the research points spent in effect would be your method of choosing a cultural path, and that would result in the various plusses that came along with it.
You could make stuff expensive enough that it would be very hard to change the course in the game, just not impossible. You'd have to tart over from scratch basically. Not a good thing to do with other empires about.
Yes, a large central city and smaller surrounding towns fits quite nicely with what I had in mind for the maps.
Geoschmo