I personally disliked the whole Natal thing from the start. Like, I thought technology-wise it was neat and all, but I saw more flaws that uses and it ended up feeling gimmicky.
It excludes a lot of people (people with disabilities/health problems, people who are not fit) from playing some games altogether, often for games that wouldn't really require it to begin with. And for games that do require it, it feels to me, you don't need the video game to begin with. Go play ball in the park and jump over benches.
I can see it as useful for training for athletes and things like that. Otherwise it kind of crosses the line for me. The Wii requires you to move, enough for you to get active when that's the point, but not enough that you have to stop playing after a few minutes.
I think it's cool as a concept, but I just can't see much use for it, if I'm making sense there.