Ok, I'll retry after the new info. Don't think there are too many characters that they will let in though.
S:
Wolf. Only Wolf. He's got great chances due to Lucas getting in. They're very similar - Japan has Lucas first, Wolf second in their list of wants, America is the reverse. It's all too perfect that they'd announce him at E3 for a release to coincide with StarFoxU.
A:
King. K Rool
I'm switching my old list around a bit, and putting him here alone now. With the ballot opened, I feel like his chances shot up. Note that he's got one of the largest threads in the character discussion, and he's requested worldwide. I really can't wait for some Croc action!
B:
Isaac, (Captain) Toad, [Rhythm Heaven something], Inkling
Isaac's got a lot going for him, but Nintendo's ignored the franchise for a bit. He does have a decent fanbase though, but it's been overshadowed by the introduction of Fire Emblem: Awakening and Xenoblade. With the poll, I feel like his chances are growing. Toad's also going strong, and the regular Toad is the only non-smash amiibo so far. He's deonfirmed as appearing as part of Peach's moveset (see below), but Captain Toad would basically be the same thing for those unfamiliar with the game. As for Rhythm heaven, I can see something getting in due to the original leaks, which are more true than not, but there's no real unifying character here. Now if we were considering assist trophies or stages...I'd put that much higher. The inklings are a special case - their game isn't even out yet, but it is a brand new Nintendo IP, and kinda stole the show at E3 last year. Plus, they're getting amiibos before Smash even has all of theirs announced.
C:
[Some 'deconfirmed' character]
Yeah, they've been deconfirmed, and we know that Sakurai has never changed his mind and gone back on his word, or put two characters in the same game in different costumes or roles. [/sarcasm] With that in mind, I don't see why it's so inconceivable that an assist trophy like Waluigi, Midna, or Ghirahim could be promoted to playable, or that a certain purple pterosaur that most people have vitriolic opinions of could get off of his one stage. All of them can be patched to stop showing up in their current role if they are promoted, or replaced with other assist characters. Or Alfonso, honestly ("Leave it to me!"). Point is, they were heavily requested enough to get thrown a bone before, why not finish the job? Now those four specifically are the ones with great chances since they have huge fanbases of their own, and their series' have gotten neglected quite a bit in this game (assuming we clump Waluigi with Wario). Laugh if you want, but I still think that it's possible.
D:
[A new third party], Dixie, Ice Climbers
Yes, with the poll, this should be higher, but I still don't know how likely it would be. Nintendo's still got loads of their own characters to put in - remember the tagline for the Smash Bros. series is "A Battle between Nintendo's All-Stars!"? I do think there are some who've got great chances because of the voting - I hear Snake, Banjo/Kazooie, Shovel Knight, Bayonetta, and Shantae thrown around A LOT. I'll see, but I've always been a bit biased against guest characters in any game. As for the other two, I feel like Dixie has potential, but the voting is severely upping Rool's chances, so it might be hurting her a bit. If people were so anti 'this series is overrepped!' and anti 'OMG such a clone!', they may be nervous to put in another Diddy-like chimp. Particularly if they can give DK some love with a huge crocodile. Ice climbers are a huge request, but 3DS issues. Now I don't know what the processing power of the 3DS is that it can't handle it when the GCN could, but the new 3DS is probably ok. Besides, if they took the controllability out of the second climber, then they would be as complex as RosaLuma and could function well.
E:
Roy, Popo (solo), Krystal, Daisy
While Roy has a huge fanbase, I think he's got the stigma of being a clone from Melee. Fire Emblem got so much love already this game since Lucina was split from Marth. Since the major arguments against the game at the beginning were in relation to overrepresenting certain series and the abundance of clones, Nintendo may be hesitant to put Roy in since he falls under both categories. In Melee, he was a clone. Just like Ganondorf was a Falcon clone, and Young Link was a Link clone. Also, His game was not amazingly popular, so most of his fanbase sees him as he was in Melee. We've got Marth, we've got a Marth clone, and we've got a dude with a flaming sword, so Nintendo may not want to rehash things - that's why we didn't get Chrom. Now if they made an Alph-esque form for Ike or Marth... that rockets his chances up. And they don't even need the announcer to rerecord a name. Solo Popo is probably unlikely since the main par of the IC's is their partnership. I'd make a cheap AI version of Nana before I see Popo alone. Krystal is also falling to the same problems Dixie is - She's female so plus points there, but she's not getting as much fanpower as the series villain, doubly so in Krystal's case, since Wolf was a character first. As for Daisy, she's got a lot against her. I think she's got nothing but getting a true alternate from Peach to get in, and hope she can get that.
F:
Young Link, Pichu, Ivysaur, Squirtle
The former two are melee clones, one of which was fully replaced by a different Toon clone, the other of whom was a joke from the beginning. I think both are unlikely as anything more than alternates. The other two Pokémon got the shaft since Charizard took over solo, and I don't know if they'll see the light of day again. There are too many arguments of "OMG too much Pokémon! Too much Genwunner!" for them to get anything more than be a Pokéball DLC, and even that's pushing it. Sad, because I loved Squirtle.