please people.. remember this is a likeness list, not want list!
as for me?
SSS: Wolf, in fact im'm pretty sure that when they release mewtwo and start tweaking lucas they will immediatly start working on wolf right away. He is popular, veteran, relevant, semi-unique and easy to implement. plus, can buy them some time while they think what to implement next.
S: none.
A: Snake, Ice climbers, King K.rool/Dixie Kong, Inkling.
B: Isaac, Rythm Heaven rep, Bayonetta
C: Captain Toad, Banjo Kazooie, Rayman, 4th MII fighter.
D: Shovel Knight/Quote/Shantae, Advance Wars rep.
E: Simon Belmont, Bomberman, Ridley, takamaru, other zelda rep, other pokemon rep, Roy, Kamui, Xenoblade X rep, S.T.E.A.M rep.
F
ichu, Baby Metroid, Diglett.
both snake and ice climbers have more popularity that people believe, and as veterasn wouldn't be that hard to implement, but both have ONE glaring issue to be resolved if they want to have S or SSS tier chances, for snake, the issue is that we don¡t know what the hell between konami and nintendo and kojima and snake, so there may be some legal dumbness in between, and for Ice Climbers, we have the 3ds and maybe 8 player smash issue. if this is posible to get fixed up, they are probably in.
Regarding King Krool and dixie, a third dk rep is a very popular request, and both of them fits perfectly, plus both are pretty popular. Dixie have the advantage of being more relevant overall to teh whole series and having appeared in teh most recent game, and Krool have the advantage of being more popular in general. still we probably only have one, so thats why they are paired. regarding inklings, i think that the only thing holding them is that their game havent been out yet (although if they are DLC we probably see them in 2016 at least) and that their game still have a chance to flop. but if teh game is a hit, or if Nintendo really want to promote thems, they are almost in, plus they are popular and potentially unique.
The B tiers i see them being VERY likely if they do very well on the popularity ballot. it's the kind of characters that nintendo could consider based mostly on popularity even if they aren't that relevant. so, i wish you luck to the supporters on the ballot
The C tiers are also likely if they do well on the popularity and have some interesting things, but also some issues. Captain Toad have the issue that we have mario everywhere. but at the same time is an interesting character, have been requested since forever and have his game. Banjo Kazooie would have the megaman effect, and his chances are better than ever, since people at rare have made explicit that they would love the idea of them being on smash. If microsoft and nintendo can indeed manage to do a good negotiation it wouldn't be thaaat imposible actually still, too many external factors to say it have high chances. similar with rayman, although i believe that there is a better chance of ubisoft and nintendo working together, but a t the same time rayman would have a little less impact than banjo and kazooie.
The D tiers have an indie rep, and advance wars rep, both of them are pretty unlikely but very original options at the same time.
the E tier have other konami reps that are higly tied to nintendo (Ganbare Simon Belmont! <3) and popular characters that have been rejected before, Or another pokemon wich is higly unlikey but not imposible. plus some new games but that are still somewhat niche.
baby metroid and diglet would make AMAZING joke characters :D