Well any kind of voting for the president of the world would surely be done electronically.. So there must be SOMEONE with enough scientific knowledge to rig it, or at least make sure someone else doesn't win .
I've personally never really liked the domination victory type because it isn't an ending of any sort--it's an implied ending. I'd be very happy if there was "absorption" so to make conquest a more bearable alternative (that is, conquer the world without having to use troops on every single city; through some other means, yet still using military might, such as taking over 70% of a given nation's population). Some people still love their domination so I wouldn't take that away from them.
Well, I'm anxious to see what others can come up with.