In almost every 'which race would win' post, the Vex gain the majority because of their time-traveling capabilities. Guys, think that argument through for a moment; that would be a classic paradox. Let's begin with the Vex losing a war, trying to turn the tables on their Guardian, Fallen, Hive or Cabal enemies. Your first reaction would be to say: "they can go back in time and do things differently, winning them the war!". This is surely not the case. Well, maybe in the Vault of Glass it is. Anyway, this strategy is impossible. If the Vex change the outcome of a losing war, then they would not have been prompted in the first place to ever go back to change time, and the outcome? They'd still be losing.