For some types of games its the future, but for games that are hardcore and require long periods of play, I can't see it taking off. Just finished Silent Hill Shattered Memories, and though it uses the motion control, and it's less distracting than some games its shoe horned into, I was still disappointed about some of the places that the motion was used.
For casual its probably the future, for hardcore, its really just adding another layer of interaction that the gamer must cheat. I mean who that's played Wii games hasn't "cheated" the movements, by making the teeniest gestures and minimal effort. I'm sure that's not the intention.