Wait, killing? As in causing games to lose life and slowly no longer exist?
Or do you just mean "hey, who doesn't like motion controls and thinks it is causing some games to be worse for it"?
The first I don't agree with, as it's quite clear games with no motion controls are doing just as well, if not better, then they ever have despite Wii being so well selling, Eyetoy existing, and Project Natal being shown off.
Are there games that are bad because developers force motion controls onto them where they don't belong or screw up implimentation? Yeah, but there are also games that do it right. Wario Shake and all it's shaking is fun, people are quite happy with Conduit, Tiger Woods and Madden managed to entertain me for a while with motion controls and I don't like either of those sports.
Some games with standard controls have been screwed up because of poor button placement, set-up, and use. Doesn't matter if it's the Wii Remote or the Dual Shock, A game developer can screw up controls with either and hurt or kill a game.
Developers need to make sure the controls work well no matter what they use, standard buttons or motion.
Not all games on Wii use motion controls and Project Natal is going to be more about user interface that it will ever be about games. Sony and Eyetoy, well I don't expect much from that.
They won't kill gaming, they won't some how be responsible for gaming as a whole to collapse, and huge money making games like Modern Warfare, Grand Theft Auto, Super Mario, and so forth will still be made and focus on standard controler set-ups.
Now what will kill gaming? Sports done outside, evil things those. Did you know you can can plat football outside for free just like you can on Wii? It's far more interactive to kick the ball then just pressing A/X buttons.