Playing and Winning in teams?

[Hagbart]

If you play as a team the hole team will win not a single player, or else it would not be a team.

[Andrew_Jay]

Maybe for an alliance victory the alliance has to stand for a period of time (20 turns maybe). Also, to break out of an alliance, ever, would be far worse than any other diplomatic reversal (breaking military alliance, MPP, trades, etc.), mayeb even make it impossible to leave an alliance.
Also, when two or more civs form a team alliance, they can have the option of giving it a name.

This way (I think) set teams can be avoided. Instead we have permanent teams that can be created later on, these alliances are permanent (so think carefully), you can win with these alliances. Perhaps a bloc can all work on the same spaceship, their land can be calculated together for domination, if they are all that's left, they win the conquest victory. Also, the bloc can be voted on as a UN leader (eg, the "Europe" bloc will be an option in the vote screen, and all its members will have an individual vote, so if it has 3 members, it can receive three votes, plus any others from independent civs).

[Firebird]

Naming the teams would surely be cool.