That makes sense, I guess.
His powers are mimicing peoples movements and voices. So That'll be why he has Spidermans web swing in MvC3, then.
If he mimics movement (which seems to be represented in the game as having moves from other characters) Seth would have been a good equivilent, wouldn't he?
There is a
14 page run down of characters at 1up.com. I didn't read it all but two things I did read was that Haggars lariet causes him to lose some health, like in the FF games and Deadpool has a teleport move that randomly malfunctions.