I loved and adored Monster Hunter for the Playstation 2. I sunk hundreds of hours into it without blinking. It was simply amazing, and I thought close to perfect. Of course, you always want more armors and more weapons... You want more enemies and more zones. And further titles provided that, but they all have really missed out on the multiplayer experience.
I tried getting into both the PSP Monster Hunter 2 and Wii U Monster Hunter and unfortunately I caught onto both of these titles a little later than I should have. I could never find groups of people to play with. And when I did find people, they never wanted to help me with my lowly and lame quests. I can't blame them for that, either, ha. I wouldn't want to do such low ranking quests either.
So, with MH4U, I am hoping there is a system in place to make it a lot easier to progress through the game alone if you have to. Playing solo shouldn't be a burden like it is. With that said, there should be a premium on group play. Make it easier to find groups of people to play with and make it easy to stay in touch with them and play with them in the future.
I have no worries about keeping the game fresh with new weapons / zones / items / combat styles, because that is something MH has excelled at. Keeping the base game the same experience while keeping it fairly new and fresh.