Pretty simple idea: allow two (or more) players to win together if they're allied/teamed-up/super-allied/whatever. I often play against AI with a friend and the only way we get to finish a game is for one of us to trigger an end condition. Maybe some sort of super-alliance that allows for Fame score sharing, so that typical alliances are unchanged and still breakable? 

Even if we'd share control of a single leader or something, It would be nice to top games off with a team win!

As an optional setting, I can see this being a great addition for co-operative oriented players.

No, I say it's a must have for alliances to be worthwile. Currently alliances are weird. It's like an unwilling accomplice as there can be only 1 winner

Thighs wrote:

As an optional setting, I can see this being a great addition for co-operative oriented players.

It could be very interesting as an optional setting as @Thighs noticed. I guess it would have to be applied before your games (like the current non-exclusive cultures mode)

Perhaps I didn't understand what you are talking about. But right now I was playing with my wife against artificial intelligence, I won an economic victory, and my wife received an “Shared” victory. We were in an alliance. Before this, when we played together and were not in an alliance, my wife did not receive a “Shared” victory.