Japan has an increasingly portable market and Monster Hunter has thrived there in the "ad hoc" world of face-to-face play. The Western markets have focused multiplayer play around online which has traditionally meant in the home, for which consoles have historically had a better play.
I think in the case of Tri Ultimate it was fairly serendipitous that we went this way but it's impossible for me to predict the future for the franchise beyond that. For MH4, we haven't announced release of that title in the West at this time nor have we discussed any platforms beyond 3DS. You'll note MH4 has moved its release date in Japan with a single SKU to later than originally announced. That team is laser focused on getting done what needs to happen to make that a fantastic from the ground up 3DS Monster Hunting experience. As such, any other discussion on this topic at this time at this point is moot. - Capcom's Christian Svensson
Svensson seems to be heavily hinting that Monster Hunter 4 might hit another platform. I guess we'll just have to cross our fingers for Wii U! Thanks to Alex for the heads up!