Sure, motion detection is in the future for games on all platforms. It was expected after the success of the Wii that there would be belated follow-ups by Microsoft and Sony (we won’t count the Sixaxis). Of course, they will say how they’ve been thinking of it all along, and their approach is totally unique.
I wonder if Sony is even going to try the usual lines when it comes out with a break-apart controller with accelerometers in each part, for dual-fisted motion detection action. Maybe we’ll see it at E3. Who wants to bet that even then it won’t work as well as Nintendo’s?