The only regret i have for Civ3, Civ4 and probably Civ5 multiplayer too is not the turn timer, but that usually no one should bother to play it. Indeed, most players quit in FFAs including myself, because i know i can't win or the game is too long. There should be a mean to continue a game even if we are loosing. The sad thing being, that i have obsolutely no idea of how to proceed.
Civ Network will eliminate the "game is too long" bit, because it may be persistent, but what about the "i can't win" part?