Wii U will do fine in Japan no matter what. It's perfect for that consumer base: small, low power, cheap, and you don't need a tv.
so 100k per week sounds about right, approx 1.2 million consoles per year, 6 to 7.2 million lifetime. I'm sure nintendo will be fine with that.
Especially given the moribund economy of that country. 3rd recession in 5 years, GDP to debt ratio of 220% (for comparison, Greece is 170%), a disastrous lack of young people vs # of old people, no net immigration, and no political will to change any of these things.
The rest of the world is a big question mark, however.