Honestly, Nintendo does not need to do anything. They have an incredible lead of 34 million units on their next nearest competitor (~85 million Wiis compared to ~51 million Xbox 360s). The Wii has the most million sellers. The only area where the Wii is lacking is the quality of third party titles and the number of million seller 3rd party titles. At this point, only a handful of 3rd party titles have performed well (Epic Mickey, Resident Evil: UC, Carnival Games, Just Dance).
Devlopers are more likely to take risks with Kinect development (i.e. "hardcore" games). Since the fanbase for the Xbox 360 is already comprised of "hardcore" or "core" gamers, that means developers are more likely to try games like Madworld or No More Heroes, on those platforms. Up until this point, 3rd party support and exclusivity for the Wii has been predicated upon the unique nature of its controls. Now that the Kinect offers a similar control options (motion control). Even with that in mind, the Wii still has a massive userbase and that is hard to ignore.
The Wii will be fine.
