I haven't read the whole thread, but in MH4U the framerate is a noticeable improvement on the N3DS. It's actually the #1 reason I bought the system. It's not a "30 vs 60" kinda jump (like, say, Dead Or Alive with 3D on and off), but on the old model it just felt shitty a lot of times, while it feels much smoother similar to the way MH3U felt.
There might be people who won't see the improvement, but it really made the game more enjoyable to me, especially considering that the game is all about timing and should be running at 60fps to begin with.