I pretty much agree it's going to tank. None of the things I've seen it do so far have really impressed me. As a player of RPGs, Survival Horror Games, Fighting Games, and sandbox action games, in roughly that order, I have seen absolutly nothing about this innovation that seems like it would improve my gaming experieence with those titles.
How does Natal make my state management and number crunching in an RPG any easier? Having goofed off with the will, I've never really felt flailing around increased the experience of playing other kinds of "action" titles either, which is probably why it's failed as a hard core gaming console despite numerous attempts.
I mean sure, we've seen it retread most of what the wii does, meaning they could produce the same stuff the wii does for old folks and kids, but really what does this do in a practical sense for me?
Right now I don't know many people who are hotly anticipating it, because it's just not that impressive.
It's impossible to tell if the thing is really awesome and they are simply keeping all of it's applications close to their chest OR if it's really just a very shallow, gimmicky, niche product with very little plausible use for the core gamers making up the 360 player base. Sadly I suspect the latter because otherwise we'd be seeing tons of demonstrations, showing how much more awesome this could make your shooter experience or whatever (given that shooters are probably the best selling genere the system has).