Gamasutra ran an interview with Marvel vs Capcom 3 producer Ryota Niitsuma. The interview covers a range of topics including the darker artistic style of Marvel vs Capcom 3 compared to its predecessor, Marvel's influence, and the need to balance the need for the game to be friendly to new players while still having demand for technical skill for advanced ones.
One of the more interesting topics was about the game's speed. Check out Gamasutra for the full interview, but here's a sample:
This version doesn't seem to quite match the maniac speed of MvC2. Was that a conscious choice? If so, what was the thinking behind that decision?
RN: The pace hasn't changed that much, but it is indeed just a bit slower-paced than MvC2. It's a totally different game, of course, but in terms of pace it is a bit more leisurely; I think we've struck a good balance. The pace of MvC2 is something that long term fans are used to by now, of course, but for newbies to the fighting-game genre, we saw it as just a bit too quick.
On the other hand, if we slowed MvC3 down too much, it would have the effect of annoying MvC2 veterans. So we aimed for a play speed that would satisfy both those veterans and people just entering the series now. I should also note that the balance will probably be further tuned and adjusted as development continues on the game, so this isn't necessarily the final version.