Well I worded my sentence badly actually, From is a great studio and is pretty good at getting a game out in a timely manner (something Japan Studio often lacks and the Vita really needs games out soon). So they're not a bad choice for a partnership really...
But the Souls universe isn't really that popular in Japan (well, relative to MH and other mega franchises), so if this game is supposed to fill the MH void in Japan, they would be better off with something new... (on top of that the multiplayer system in the Souls game doesn't fit well with the local co-op system that made MH such a big franchise).
Edit: Well seeing the very dark/creepy art style, I'm going to guess this isn't geared toward Japan specifically and more toward the west, thus From Software and the Soul franchise would be a good choice.