If this were to happen (it won't) Monster Hunter 4 would I would guess get around 1.5 million lifetime sales on Wii U (and cause the Wii U to go way up in Japan) which would be a retraction for the series (Tri had 2.1 on Wii and 2.2 on 3DS 0.4 on Wii U - those include the 3Ultimate rerelease of course).
What I think is a more likely scenario to happen (and while I want this to happen I said more likely, not definite unfortunately) is that MH4 comes out in Japan on 3DS this fall with a re release as MH4U on the Wii U in Japan in Summer/Fall 2014 then the NA/EU release late 2014 of both the 3DS and Wii U versions of MH4U like they did MH3U outside Japan.
The original Monster Hunter did around 1 Million Total Lifetime Sales (0.5 on PS2, 0.23 on PS2 again as MHG, and 0.25 on Wii at MHG in Japan)
Monster Hunter 2 did 0.63 Million just on PS2 (not sure why that didn't get a PS2 and later Wii MH2G rerelease).
Monster Hunter 3 has done by far the best doing 2.1 Million on the Wii, 2.2 Million on the 3DS and 0.4 Million on the Wii U (as MHTri and MH3U) totaling around 4.5 Million - but this is mainly because of the popularity of Monster Hunter Freedom line on the PSP I think.
Nintendo fans seem to be embracing Monster Hunter (even outside Japan a little, still niche but not quite so much) so I hope to see 3-4 Million 3DS sales (as MH4 and MH4U) and around a million Wii U sales (as MH4U) hopefully coming out just ahead of MH3's total eventually.
I'll be interested how they follow it up, if they actually do the MH4U or if they maybe resurrect the Monster Hunter Freedom line. They were doing regular Monster Hunters on home consoles and Monster Hunter Freedom games on handhelds but now MH4 is as of now handheld exclusive, maybe they will move Monster Hunter Freedom to consoles - or maybe Monster Hunter Freedom 4 (or 5 if they decide Unite counted as 4) will be PS4/Vita and if so I'll probably finally have a reason to buy a Vita, or maybe the next Freedom will be on WiiU while the regular will be on 3DS but I don't like that setup.








