The other day 3DS just topped Wii's lifetime sales in Japan. Granted, Wii is still out, but it's not catching up at this point.
I'm not worried about Wii U as a console. Nintendo knows how to be Nintendo and that alone will keep the console afloat for the duration of the generation. This is a blessing and a curse. If you're looking for anything beyond strong first party titles, you're barking up the wrong console. That's where frustration sets in with a lot of people. I wish I could buy one console for all my gaming wants, but I didn't buy Wii U without knowing what I was getting into. Between Wii U and 3DS, I have too many games on my plate this holiday season.