The Wii sold fucking poor in Japan but the Wii U is a console disguised as a handheld and will have Monster Hunter games probably over it's whole lifetime. Maybe even with extended connectivity to the 3DS like 3G will so. I really think the Wii U will easily outsell the Wii's numbers in Japan. We'll see if it will have success in the west. But I don't see it selling less than 60 million world wide lifetime.
Ongoing bet with think-man: He wins if MH4 releases in any shape or form on PSV in 2013, I win if it doesn't.