Concise description:
If at the begining of a player turn, that player has 67% of territories, 67% of armies and 67% of income, then the game is won by Domination.
If that's too low, make it 75% or 80%
How this will benefit the site and/or other comments:
It will avoid boring and tedious endgames, when its clear who has won yet the game must continue.
It will make for a more climatic end game.