Reviving both Ultimate Marvel and the Marvel Mangaverse might be a bit overly ambitious, but I'd definitely be in favor of it. I still have some old issues from the Marvel Mangaverse. And I think Momoko would be perfect to spearhead that universe, given her familiarity with the style.
But that same style...I honestly don't think it was the issue in Ultimate X-Men #1. The art was fine. It was the actual substance of the story that was lacking. It really did not have the substance of an X-Men comic. It felt more like a generic manga that just happened to have a character whose name was identical to an X-Men character. And I don't think that's a good approach for building up this series alongside the other Ultimate titles. But I guess time will tell. Maybe there is a larger plan. It just hasn't been announced yet.