I would like a scenario about the expansion of the Greeks in the Mediterranean sea in the 8th-5th century BC. Let' say there are 5-7 competing Greek civs among them Athens, Sparta, Corinth, Argos, Thebes. They can only found (allied) city-states, not city of their own (they can choose the CS and the related suzerain bonus among many CS, so it is a central element of the strategy).
When they develop, they have to choose between three ideologies: Democracy (good for specialists and quite rough handling of allied CS, e.g. annexation, think about the Athenian-controled league of Delos), Tiranny (stengthens military, gives the ability to found their own cities, concentrates production and food in the Capital, think about Dionysius I of Syracuse) and Oligarchy (for commerce-oriented players). And there a ton of ideology-independant civics for common cultural traits shared in the Greek world.
Persia is awaiting to conquer and puppet as many Greek players and CS as possible. And Carthage to control all the luxuries.
I had started an Civ V mod of this scenario many years ago anf then I got quite busy and I could not finish it. But I think I will give a try again when the modding tools are availabe again.