It's hideous. I can't believe a company would do this to their consumers less than a year after its original release. I wonder how much of a pay cut Iwata's going to get now to make up for the inevitable revision with this thing in bay.
Anyways, the Famitsu article where this all went down (alongside Monster Hunter Tri G for 3DS):

The MH3 water elements that were absent from PSP's Monster Hunster Portable 3rd, also an expanded version of MH3, are in MHP3G. The game is said to have a slightly different control feel for its water segments, while still retaining the overall feel of 3's water play.One new control feature will make use of the system's lower touch screen. By touching, you'll be able to make your character automatically turn to face larger beasts.
Other features mentioned in Famitsu include local wireless play and a new main cover monster named Blakidios (I'm not sure if this is a totally new monster of it it's from a past title -- the name doesn't come up in the Monster Hunter Wiki).
A release is planned for the end of the year, Famitsu reports. The game will be playable at Tokyo Game Show next week.
Vita am doomed.