Courtesy of Cheesemeister‘s translation of the Nintendo Direct event, we now know that Wii U’s Monster Hunter 3G HD will be based on the 3DS version. You will be able to transfer saved data from the 3DS version over to the Wii U and vice-versa, and all items, skills, and equipments will carry over as they are from their respective console.
You will have the choice to play with either the GamePad or the Pro Controller. You can also use the GamePad as a data display if you choose to play with the Pro Controller. The neat thing is that besides the fact that you have up to 4 player online mode, but you can also get some local multiplayer with 1 Wii U and up to 3 other 3DS.