1: It doesn't support force feedback or other such goodies, and
2: The left and right triggers are mapped to the same axis, which means that you can't use them both at the same time.
I get that it's a little confusing, but it's not as horrid as, say, THQ's decision to license an arcade stick for WWE All Stars that can't even support all the functions you need to play the game.
We should have this "problem" every year.
Which is why I really appreciate their integrity in making this choice, even knowing it will cost them money.