Wand and NATAL are gonna fail. #1 It's too late to try and implement that kind of stuff into the systems. Either you integrate it to all PS3 and 360 games (thus alienating people who don't want to play with motion controls) or split up how games are developed...and just piss off developers who have to make a regular version and a motion control version
#2 M$ and Sony are doing this only because the Wii is popular. But the people who buy Wiis are not the same people who buy 360s and PS3s. The people who buy Wiis want to play Wii Fit, Wii Music, Game Party, etc..for the most part (as evidenced by not only the sales of casual games, but the sheer amount that are on the Wii). They don't want FPSs and over the top action adventure games. Meaning if Sony and M$ want to capture that audience...well they're going to really piss of the "traditional gamer", which is the typical demographic that buys there systems
With that all being said...people need to stop saying that NATAL may be a game changer. Conversely, people who retort "you forgot about the Wand/GEM"....stop doing that as well. Unless you think people are going to spend $300 on a 360 or PS3, then spend however much it costs to get the damned peripheral.....THEN buy a game. Yea....I don't think the casual market pie that Sony and M$ want a piece will be too accepting of that