I'm not seeing it. In some certain cases yes. Red Steel 2 should do okay but will it have a real online multiplayer? And splitscreen? Co-op mode? Don't know and without those this might just be a curiousity to 'core' gamers. Not a purchase and certainly not a system seller.
Now I real Jedi Knight game with real online and excellent light-saber battles, that WOULD be a system seller. Except I fear Lucasarts would have to get someone else to make the game to make it the calibur of game all the fans want.
Sports titles, particularly TigerWoods, Tennis and Baseball could steal fans away from the HD systems thanks for WM+.
But besides sword fighting and swinging a bat, tennis racket, golf club what would WM+ add to any traditional game title? Not much.
The problem is to use WM+ correctly in all other cases developers will need to make new types of gameplay (like a FP Sports game - say Ultimate (freesbie team sport)) but traditional gamers generally avoid new innovation and stick to the tried and true. So publishers will have to be savvy enough to both know a good new game concept and understand A) They need to market it to the people not currently playing 'core' games and B) How to.
I fear most 3rd parties are too big and too set in their ways to adapt. They will only ever half-ass it and only ever get half-ass results. But if any 3rd party publisher can stomach taking the risks (the same risk Nintendo took making the Wii), the rewards will be equally great as Nintendo's