This don't make no sense at all. You've said that motion controls are great in MG2 and MP3, it's clear they work great for WSR, and now we're back to
motion controls=CASUALIZATION
Three games doesn't change the perception. The perception is there or third parties wouldn't almost exclusively dump casual focused garbage on the Wii and Sony and MS wouldn't be all casual focused with their motion control. Like it or not the videogame industry associates motion control with casual gaming.
Regarding jaded Wii owners I agree with BlackNMild2k1 that they probably already bought a PS3 or X360. Hell that was like the way you did things if you wanted more. Hell, I figure that jaded Wii owners are the last people to want anything to do with Move or Natal. If you have a problem with the Wii odds are motion control is a big part of that. I personally like how PS3 games use normal responsive controls and that I don't have to fight with waggle the whole time. So for me to buy Move, well ****, Sony has to REALLY impress me.
And as for the existing Wii casual userbase, I don't think they'll buy these. I wonder if they'll even buy a Wii 2. The Wii was the "it" item a few years back and created a frenzy. Can Nintendo recreate that again? I think we still have to see if these people want to regularly buy videogames or if the Wii was just a one-off purchase. In my day-to-day life the Wii is no longer the hot topic. I know a fair chunk of people that bought a Wii for Wii Sports, bought Wii Play and Wii Fit and maybe a Rock Band or Guitar Hero game and that's it - they haven't used it in over a year. They're not talking about NSMB Wii or Super Mario Galaxy 2. We are. They're not.
A big part of the Wii's sudden success was that "OMG YOU SWING YOUR ARM AND THE DUDE ON SCREEN SWINGS THE RACKET" reaction. Wii Sports was a monumental game. How will Move or Natal or even the Wii 2 create that kind of a reaction? We don't know what the Wii 2 will be so maybe Nintendo will come up with something. But I don't think ANYONE is going to see Natal and get blown away but what looks like the same thing but without a controller.
I think the only strategy that could work, and Sony has sort of hinted at it, is to find a good use for it in hardcore games which is something Nintendo hasn't really done. While Nintendo is showing off Wii Party, you show off Halo with good responsive motion controls and Nintendo looks like a joke in comparison.