SourceGaming did a poll on DLC characters and made a video on the Top 50.
Banjo, Sora, and Dante are the only ones I can truly get behind 100%, and I'm not even a fan of Banjo-Kazooie, Kingdom Hearts, OR Devil May Cry.
Like everyone else, I think Erdrick is all but confirmed. I also think he's really boring and lame.
Klonoa would have to be my #1 personal choice if Sakurai personally asked me to pick a third party character with no regard for what anyone else wants, and it makes me happy that he seems to be a popular choice with other people as well, but I think his cult status and utter lack of relevance in gaming right now mortally wounds his chances.
Monster Hunter would be boring, but I could accept it by virtue of it being so odd that we have a Monster Hunter boss, but no playable rep. Travis Touchdown and Lloyd Irving wouldn't be very exciting for me, but I can still see them happening. Ryu Hayabusa would be cool-ish, but I share the uploader's concerns with his moveset being too derivative, since we already have two ninjas in the game (as well as one character named Ryu). 2B would be cool, I guess, and even though I don't care about Nier, I still think she has a chance, given that we have three M-rated characters at this point.
Crash and Spyro can't happen unless they're BOTH in the game, imo. They're basically counterparts, and you can't have one in a crossover fighting game without the other, as far as I'm concerned. And, frankly, wasting two DLC slots on these two characters would be kinda lame. I just don't see it happening for either of them. Marvel vs. Capcom 3 proved that both Amaterasu and Phoenix Wright can work in a fighting game, but I don't personally expect or want them. Chrono Trigger is a cool game, but we don't need Crono in Smash. Neku is eh.
I don't see any first party characters happening, which rules out Porky Minch. He would be interesting, though.
The following characters have absolutely no place in Smash, as far as I'm concerned: Steve, Arle, Quote, Goku, Master Chief, Reimu, Sans, Hollow Knight, Cuphead, Monokuma, Professor Layton, Scorpion, Lara Croft, Heavy, Leon Kennedy, and ESPECIALLY Doom Slayer.
The following characters are deconfirmed, as far as I'm concerned:
Geno,
Shantae,
Rayman, Rex & Pyra, Elma,
Dixie Kong, Tails, Chibi Robo, Paper Mario, Bandana Dee, Karate Joe, Chorus Kids,
Waluigi,
Skull Kid,
Isaac,
Shadow, and Ashley. Some of these characters deserve to be playable, some don't. I've bolded the ones that I would've liked to see.
Some characters simply work better as bosses or Assist Trophies, and I think people need to learn to accept that.