is it possible to associate building construction with some kind of reform? if it was, perhaps this could be used to represent the ability to assimilate cultures into an empire, suppose that once the romans conquered so many cities, they would then become more proficient at annexing them. This could perhaps reduce the lack of late game historical accuracy. For example, before alexander there was no hellenic culture in persia, yet less than 100 years after his death the greeks can build level 2 governments across formerly persian lands. had alexander decided to conquer europe instead, then persia would lack hellenic culture and the greek level 2 governments would extend into spain and italy. i'm not sure what the limits of scripting are and i know that this is tricky but it would be interesting to see.