Conspiracy theory time...
What if they are slowing production in order to deplete stock because they are getting ready to release a Wii on steroids?
Think about it. People complained that the Wii has a horrible online capabability. Well, compared to the 360 they do. Heck, even compared to the PS3!! Graphics are seen as last gen quality. Games right now are seen as gimmicky and shallow.
Now if they reintroduce the Wii that's better, they can improve the graphics quality, streamline their online gameplay, and make more people happy. Of course the people who would be the most upset will be the ones who have already purchased the Wii. But that's what happens when technology gets better... :