After getting a long lecture about Sony’s wand/camera tech on Empire forums it seems to me that this setup uses parts of Wii and Natal. The PSEYE can apparently also track your head ( Not the full skeletal structure like Natal though )and body like Natal while the wand plays exactly like the Wii controller. If you add both these features in a FPS like Metroid Prime for example then the EYE can track your head to move the camera i.e look left and the games camera moves left while the wand is used as as your pointer to shoot like the regular Wii mote.

Cant comment about Natal because i feel we know very little but personally i cant picture myself moving my arms and legs around in fresh air. I need some kind of feedback or something in my hand ( Maybe you can hold real world objects to compensate and the Natal camera can read them but the problem is that Sony already filed a patent for this so i dunno ). Seems to me though Natal is more for casual games while the wands and Wii mote can incorporate this into core and casual games.