I don't think there are legal issues with Disney characters, a lot of them are in the game as townspeople so they definitely have a chance of being in the game one day! My biggest wish is still Robin Hood and on number two it's Scar for me.
I'd also like them to add a bit more female characters in the future. It's great that the two officially announced Disney characters (Maleficent and Merida) for 2.0 are female characters but we could sure use some more. I'm thinking about characters like Mulan, Alice, Belle, Maid Marian, Esmeralda, Nala, Mary Poppins, Quorra,...