|Note the 7 boxes|
1. Grass Type Pokemon (Pokemon)
Okay, I know this isn't a specific character, but let me explain my reasoning here before you shut me down on this one. They've already announced Charizard, the fire type from gen 1, and Greninja, the water type from gen 6. Because they removed Squirtle and Ivysaur, and replaced the water type, it would logically follow that they will replace Ivysaur with another grass type. Some of my friends have speculated that this new grass type will be from a middle generation (probably gen 4), but because Lucario has already been announced as a returning fighter, I don't see why they would add another gen 4 Pokemon.
2. Pac-Man (Pac-Man)
This one sounds like a stretch at first, but if Wii Fit Trainer is a thing then nothing is out of the question. Considering certain items from Namco games were displayed in the Nintendo Direct, it is a possibility that Pac-Man would join the roster with fellow video game icons Mario, Sonic, and Mega Man.
3. Dante (Devil May Cry)
This one might be just wishful thinking, but I might as well still add it. With the relatively high presence of 3rd Party characters that have already been announced, the likelihood of this actually happening is small, but if Capcom let Mega Man into the game then why not Dante? He already has a little experience in the fighting genre, and his combination of gunslingling and swordplay would bring a reasonably unique play style to the fight. And Capcom is dying not-so-slowly anyway, so it could be like a swansong to them. Just put him in it. Please.
4. Crystal/Falco/Slippy (Star Fox)
We've made a lot of jokes about Crystal being in the game, but as of yet no Star Fox characters other than Fox himself have been announced. Falco has not even been confirmed as a returning fighter, prompting me to think that either a. He's late to the party or b. He's not coming at all. If he isn't making a return, I feel like either Crystal or Slippy have the best chances of taking his place, Crystal because of the potential of her staff and Slippy because, well, he's Slippy.
5. Mew (Pokemon)
Because Sakurai is a troll.
6. Dolph Lundgren