Civ3 had something like this, where the turns of anarchy incurred when switching governments increased with the number of cities in your empire. It's been too long since I played Civ4 to say for certain, but I know the period of anarchy when switching civics also varied (when one is not in a golden age).1) How often (on average) do you think the ideal is for switching civics ? (How many turns between switching)
It would be interesting (in theory) if how often you could change policies was based on the communication infrastructure of your civ. A one city civ could change every turn, a two city civ connected by a roads or water could change every two turns.