FLUDD was freaking useless. It seriously would've made more sense if they let Mario keep his spinning move, while giving Luigi the vacuum from Luigi's Mansion.
But then again, Luigi needs some tuning. I'm glad they changed his up special in Brawl to something you can actually use to jump back in the stage. Although his specials don't vary a lot from Mario, we can't forget he's still his brother, so it actually makes some sense he has some similar looking moves. Just change his specials a small bit to make them more related to games where he has a bigger role (like he has any besides Luigi's Mansion). Mario can keep his specials from Melee.
As for other characters. Give Wolf some different specials and he can do, but Falco is simply too much of a Fox clone. Although his specials got a change in Brawl compared to Melee, it seemed more like just a quick escape from Nintendo to make him a bit different. I won't mind if Falco gets removed, same with Lucas. They're clones and you know it.
Ike is good. Roy was just a Marth clone, Ike actually has his own specials.
No more new Links. No matter if it's Young Link or Toon Link, a clone is a clone.
Ganondorf, as said multiple times before, has so much to offer to make him different from Captain Falcon. Nintendo has to use that and he'll be a perfect character.
Make Zero Suit Samus and regular Samus like Zelda and Sheik, offering the player to switch between them during play. It was really annoying that you were forced to use a Final Smash or that dumb button combo before the match started to use Zero Suit Samus.
I never really got the whole Mewtwo to Lucario change, but I guess it just fits better within the Brawl storyline (Mewtwo would go as a bad guy). I still find Mewtwo easier to use than Lucario, but that can be just me. I don't mind if they add both though, Lucario is different enough to go as a seperate character. Just give one of the two different specials.
@Lord Vordred
I don't see Non-Specific Action Figure become a playable character, he's simply to minimal. They most likely will just make him a trophy, but nothing more.