Lately I've been wondering if Monster Hunter 3 Ultimate will finally be the game to popularize the series in North America. I think that it has quite a bit of momentum going for it.
If you look at the metacritic page for Monster Hunter, it is pretty clear that over the years reviews for the game have become more positive. I'm sure this is partly because the games have improved but I also think that it probably has something to do with people becoming more accustomed to the series.
The biggest thing I'm noticing is just a lot more buzz surrounding this one, and the franchise in general, lately than ever before. This game seems to have more people excited than any previous game and Monster Hunter 4 seems to be the same. Capcom has been doing a pretty good job of talking the game up on Facebook and releasing a patch to play on the gamepad in April was a great added incentive for gamers.
I don't know when sales numbers will be released, if they ever are, but I'm really hoping that Monster Hunter 3 Ultimate is the entry that finally makes the series click for North American fans. I know this is the entry that has clicked for me.