! SSB4 new (or some who should return) playable character addition possibilites
Dixie Kong - Donkey Kong Country 2+3
Knuckles the Echidna - Sonic the Hedgehog
Chaos - Sonic Adventure DX (Gamecube)
Metal Sonic - Sonic the Hedgehog
Giraheim - LoZ Skyward Sword
Demise - LoZ Skyward Sword
Dark Samus - Metroid Prime 1, 2, and 3 (Gamecube)(Face it this is the only canadate for another Metroid character aside from Ridley)
Ridley - Metroid Prime 1, 2, and 3 (Gamecube)
Roy - Fire Emblem (bring him back dammit)
Mewtwo - Pokemon (same as Roy)
Banjo Kazooie - Banjo Kazooie + Banjo Tooie
Isaac or Matthew - Golden Sun
Garet or Tyrel - Golden Sun
Alex - Golden Sun
Bowser Jr./Shadow Mario - Super Mario Sunshine
Pokemon Trainer 2 with Cyndiquil/Bayleef/Feraligatr or Mudkip/Grovyle/Blaziken or Turtwig/Prinplup/Inferniape or Tepig/Servine/Samurott
Captain Louie - Pikman 2
Skull Kid - LoZ Majoras Mask
Young Link - LoZ Majoras Mask (with Mask Transformations so it would be like PKMN Trainer)
Paper Mario - Paper Mario, Paper Mario 2, Super Paper Mario
Paper Luigi - Paper Mario, Paper Mario 2, Super Paper Mario
Paper Bowser - Paper Mario, Paper Mario 2, Super Paper Mario
Bomberman - Bomberman
Amaterasu - Okami
Geno - Super Mario RPG
Megaman - Megaman X (all)
Zero - Megaman X (all)
Goemon - Mystical Ninja Starring Goemon
Mii - Nintendo WiiI created a list of characters I think could be in (and some that should return)
Any opinions welcome any additions I may have missed are welcome too. I like to do this when there is a new SSB game coming out lol.
You remind me of a younger, more hopeful me.
My thoughts:
! Sonic characters: no thanks. Third party characters, imo, should be restricted to heads of franchises. I'd rather see a capcom character than another sonic one.
Donkey Kong characters: Dixie is one of the more possible ones from your list given she was almost included in brawl, having actually been coded in and then dropped I believe. Along with her I wouldn't mind King K. Rool, he'd be fun.
Zelda characters: Ghirahim, imo, is a shoe-in. Demise would make a great boss character. I would still want Vaati or Midna/wolf link, but I think the time for those characters is long gone. Which is also why I don't really expect skull kid and young link.
Metroid characters: I really really want Ridley, but once they went with the boss route for him my hope for him left me forever. Personally not interested in Dark Samus. Not sure who else could make it, since I haven't played the most recent metroid game (Other M)
Fire Emblem characters: While Roy was fun, there's a lot more characters in the FE universe that would deserve a spot and would have unique fighting styles as opposed to being clones. My list: Lyn, Hector, Micaiah/Sothe, Ephraim, Lyon, Soren, Black Knight. The ones I wish but would be impossible and very unlikely: Joshua (SS), Nephenee (PoR, RD). Sadly, there haven't been FE games in a while in the US since Shadow Dragon, so not sure if any character would make it, unless a 3DS Fire Emblem came to exist with new characters.
Pokemon characters: I'd say Zoroark has good chances. Would love Mewtwo to come back. As for the Pkmn Trainer idea, I'd prefer if they did something like having a Black Belt with Hitmonchan/Hitmonlee/Hitmontop or something of the sort. Still find it unlikely.
Golden Sun char.: Yes please!! Sadly, I feel like that franchise hasn't gotten enough attention. No Golden Sun for 3DS ambassadors was a horrible sign.
Mario characters: I like Bowser Jr. and have wanted him in before, but I'm not a fan of more mario characters, except perhaps geno who is unlikely. Same applies to Paper Mario characters.
Louie: unnecessary clone. I'd say let's wait and see if Pikmin 3 pops up next E3, that might affect chances for another from that franchise.
Mii: Meh. Could happen, but color me uninterested.
Third Party characters: Huge YES PLEASE to Amaterasu. Fantastic character from a fantastic series that has been on wii, ds, and would be perfect for WiiU. But since Ammy is capcom, the more likely result wouldn't be as pleasant. Same goes for megaman … capcom has been horrible to megaman recently, so not sure if they'd allow for it. Goemon has been very obscure for a while. Banjo is no longer nintendo ...
! Things you didn't think of:
Kid Icarus franchise: That dude with the huge sword, maybe Medusa depending on how they handle her size as a villain. Sora is in charge of the new kid icarus, they're bound to include stuff about it in their next game.
Square Enix: Talk about sora ... I'd love Sora! But this is unlikely.