Just briefly looking at the game.... the same players didn't start in both games.
Osborne on the yetis gets 40 minutes 1 game, 2 minutes another game.
That aside. yes GDP makes that much of a difference. It's not that overpowered if you can mix up your offenses, or change the pace once in a while. Remember, its "overpowered' (Your words) both directions, positive and negative.
Its a nice way to cancel out HCA if done right too...