I agree I don't see what makes Natal so different until now...
Eyetoy games looked meh to me, even Eyepet while charming looks mostly aimed at kids, so until I see something new color me unimpressed.
I'd say the same thing about Sony motion control wands or wiimote games by the way...
The difference is the Wii is already very successful while Sony and MS have to convince us to buy their competitor products. I suspect it will be very hard since Eyetoy and PSEye didn't sell a lot.