As they already have the satisfaction of winning they can choose thier "man of the match" to take the trophy and end the game with high scores and firm allies for the next game
IMHO this is exactly the worse scenario ever for these reasons:
1. If it is "satisfying" and maybe honourable to end the game in an alliance of two players, then one can bet that another alliance, of THREE players will challenge with some "satisfaction" and some honour the above alliance. Soon a 4-players alliance will rise (again, keeping a bit of satisfaction and honour), then a 5 players one (with still some trace of satisfaction/honour), and so on and so on, till the whole game will polarize on 2 giant alliances. Who will win? Yes you're right: the biggest alliance. (I would say, without the least intention of offense: the alliance of those who care less about both satisfaction and honour).
2. If the above point is not as annoying for you as it is for me, then think about the outcome scenario: "firm allies for the next game". Here it comes what I would call "the longturn.orgization" of GreatTurn: big powerful alliances that cross matches and don't arouse from each match's specific conditions and "mood". No matter what happens: player x will always be a good ally, player y will always try to kill you. Or even worse, you'll always be a lonely renegade because everybody knows you once "backstabbed" someone (and this is a small town). Then, in a not far future, even being a noob will bo a problem, because you'll have to be accepted in one of the alliances. How boring.
The ideal scenario? Secret identities. Names of players are kept secret till the end of the game, and substituted with convenient aliases (Nation leader?). This would be the only way we can guarantee an environment in which "life in the other world" simply cease to exist, and players will be set free to behave as they want without fear of being judged in the future. But this is another story.
My 2 cents.