That game is technically a sequel and it sold well before on the PS2. Also, 3DS development is cheaper. It also is an RPG, so coming up with movesets isn't that difficult to pull off since balance isn't truly an issue (there's no vs mode against other players, I think).
If PSASBR sells well, I expect that more companies will sign on and add their characters to the game for a sequel. Less risk that way.
I made a Marvel vs Capcom 3 Jukebox: http://www.charlietang.net/umvc3/ I also made a Duodecim Build Generator: http://www.charlietang.net/dissidia/012.php
Pretty sure it reuses a lot of stuff from Namco X Capcom Since it is a sequel. Also it's a grid based rpg. My guess is they are using old Dante cause its probably being reused from Namco X capcom plus he appeals more to the Japanese market. Game looks great though.
Currently playing:Resident Evil 6, Dead or Alive 5, Tokyo Jungle, Dishonored, One Piece Pirate Warriors, Retro City Rampage, Borderlands 2