We're going through the *same exact thing* with our DS5 right now!! His behavior the past few weeks has been bad at school. Our DS5 started Kinder at 4, so he's already young for his grade. We're having the same reading issues w/monotone voice and reading levels.
As for the Wii, he's also obsessed with SMB. However, anytime he gets anything but a green (good behavior) in class, no Wii. So lately with the bad behavior, he hasn't played it much. I also limit the time he can play. Mine is the same way about it - he writes stories about it, talks about it, pretend plays about it...
I have no real advice for you, other than it's funny how much your story is like what we're going through right now.
