Just about everybody who's been involved in Star Wars at one point or another has expressed their interest in making an appearance in the new film, and that's fine, granted that there's a need for their character to come back. Samuel L. Jackson is one of the actors who has openly said that he'd be up for coming back, though he's perhaps the perfect example of a character who would be largely unnecessarily. Firstly, he's dead. Secondly, he never really had a super-important story function in the first place. As long as we keep characters like that down to minimum, there's a good chance that fans will be able to take this movie seriously instead of it accidentally turning into some self-congratulatory Star Wars reunion party. If there's room in the narrative sense to bring back iconic characters like Luke, Han and Leia, that's fine, but in most cases, there's not going to be a good enough reason to resurrect characters - especially dead ones - for the sake of it. Sorry, Sam.