Not every character who has appeared in previous Smash Bros titles will be appearing in Super Smash Bros - because there isn't enough time to recreate them all.
Designer Masahiro Sakurai explained the reason when NowGamer asked if all the previous characters will return.
“I can answer that: no. We don’t have the time to fully recreate every single character who’s been in Smash Bros at this point. Adding new characters is not a simple addition – it’s really multiplication. The amount of work, adding a character is multiplied and becomes bigger and bigger as you go. We can’t because of the amount of work it takes. However, I do believe I understand that each character has its own set of fans out there who really like that character. So we’re not going to cut characters out of the way, we’re going to put in as many characters as we can, we really want to do that, because it’s good for the fans and good for all of us. But in the event that we do have to cut some characters, I’d like to apologise in advance to those fans.”