Robert Seddon has linked us to an article on GoNintendo, that reports an interview by NGamer with Ryota Niitsuma, producer on Tatsunoko Vs. Capcom, in wich he revealed that the team had some plans to add the Phoenix Wright character in the game, but in the end he was canned because of his special move:
Because Phoenix Wright only has one move, ‘Objection!’, we struggled. We designed a move for him: when he says objection, the actual writing attacks the opponent. However, ‘objection’ in Japanese is ‘igiari’ – it’s four characters, whereas ‘objection’ becomes ten [sic. It’s nine, actually.] When we localize, the balance of the game gets destroyed because the move becomes bigger. There’d be no way of avoiding it! We had to remove him for these reason. In the future, it is one of our aims to get him in.
That sounds like a weird reason to remove a character. Why not to remove just his special move? We’ll never know.