Many strategy games suffer from the overcomplex mind boggling endgame syndrome, where, even if yo uare sure you will win, you have to play 3-4 hours, just to be sure to snuff out every single enemey left somewhere on the map.
Master of Orion dealt with this in a very elegant fashion, allowing players to be "voted" winners, when you had a certain amount of power. I'd REALLY Like this kind of option built into this game, so that, in large maps for instance, you wouldnt have to track down that one last elusive hidden unit that is nearly invisible somewhere on the map.
There could be multiple ways to win - owning 4/5's of the map, ensureing alliances from all the other players, economic victory, the Master spell, and so on...