this seems like a great idea, i cant wait for Portal 2. but yeah i just dont see how this can be considered fair.
i know there are a lot of great console gamers out there, dudes with amazing skill on a controller. but from a person who's been playing FPS games for years and has competed before and all that...im sorry but you cant match the speed and accuracy of mouse and keyboard with a controller.
mind you its not like this game requires the players to land headshots on each other, probably why this will actually do really well if implemented correctly.
you couldnt do it with competitive FPS games though.