I don't know if I'd buy Monster Hunter if it didn't have online. For me the game all about getting together with you guys to take down some giant beasties. Even though I finished the campaign mode it just felt stale in comparison to online! You guys made MH Tri for me!
...on a side note, as Ville says, Monster Hunter for WiiU would be epic, the touch screen for item management/usage would help. Also, it'd be nice to take the map off the main screen but still have it on the Gamepad.