I haven't played this game in over three years because I hate it, but R.O.B. was the best newcomer. Unfortunately, I don't see it returning in the next game. I also liked King Dedede though, and he seems likely to return.
@DrFinkelstein I'd rather not get into that because it never ends well, and I don't want to turn this thread into arguments. I know I've said a few things on it here though, which you can find if you do a little searching. It was in some Smash thread and there can't be too many of those. As for the new one, I'm watching it, but haven't seen anything yet to make me optimistic. I'm actually worried about it being too much like a regular fighting game since it's being made by a fighter team, though I s'pose that's still better than Brawl which was made by an RPG team who only know spectacle and not actual gameplay. All I can say so far is that the graphics are much better, and I'm glad they don't have the dark colouring and dramatic shading that makes Brawl dull, drab, and depressing.
Just unlocked Toon Link, Wolf, and Jigglypuff! Needless to say, I am so happy to have the first, the second I hope doesn't make it back into the Wii U version (or at least replaces one of the other similar characters). As for the third... I say bring her back. I know she's similar to another character but her unique moveset always makes for fun and sometimes funny matches. Also, do I have to bother spoiler tagging this stuff?