Limited city exchange
Limited city exchange
In Civ5, when you conquer a city from not its founder, you have an option to "liberate" it and return to its previous owner, that increases your "soft power". While reviving AIs is not that interesting, I think in multiplayer games there should be an option to allow some city trading which is usually totally blocked: give a city back to a player of your team, or give it to your ally within a turn you conquered it. Likely, in v.3.1 it's already done, but it has long way to go to Longturn.