This game really need victory conditions that declare a winner soon as possible after the game is decided. After the game is decided it can take twice as long, or more, to actually finish the game. A set of good victory conditions would cut down average playtime by a large factor. This would increase the multiplayer experience, let everyone play more games and try more strategies, and, with well designed victory conditions, add strategic depth.
What fun is it to have to spend hours and hours to mop up a game that you already feel is 90% decided, and requires no further strategic consideration on your part?
Of course, for those who want to, there should always be the option to play to the bitter end.