I don't know whether she necessarily has 0 chance, considering she at least actually managed to get a Mii Costume in Super Smash Bros. Ultimate, but I'd really like to see Shantae make it onto the roster of a future Super Smash Bros. game. She originated on the Game Boy Color and has branched out onto other platforms since, so it would be neat to see recognition for how far she's come. I feel like she has a ton of moveset potential between her transformations and the pirate stuff from the Pirate's Curse game.
Another addition I'd like to see that I'd say has low chance but not necessarily 0 chance is a full evolved Grass-type starter Pokémon. As someone whose favorite type is Grass and who tends to pick the Grass starter most often, I feel kind of disappointed that the only Grass-type in Smash Bros. is middle-evolution Ivysaur as part of Pokémon Trainer's team, whereas we have Chrizard and Incineroar for fully evolved Fire-types and Greninja for the fully evolved Water-type. If we count Squirtle, we have two Fires and two Waters but only one Grass-type. I feel like they missed the boat with not adding Decidueye, but hopefully someday maybe another good Grass-type addition will come along. I'd say the chances are fairly low though as I think Fire and Water are usually more popular.
As for some characters that I think truly have 0 or next to no shot at actually being included but that I'd like to see:
- Scorpion or Sub-Zero from the Mortal Kombat series. We have Ryu and Ken from Street Fighter, Kazuya from Tekken, and Terry Bogard from King of Fighters, so I'd really like to see someone from Mortal Kombat being added and these two are the most likely, with Scorpion being the likelier of the two. They probably won't due to the graphic violence, but I feel like you can still make movesets that capture the character that would fit the Smash style.
- A Fire Emblem character that either isn't the main Lord of the game and/or doesn't primarily use a sword. Nintendo uses Smash Bros. to advertise the latest Fire Emblem games and as such they always opt for the main character of the newest game. Unfortunately, most Lord characters tend to use swords, save for Hector from Fire Emblem: The Blazing Blade and Ephraim from Fire Emblem: The Sacred Stones. There are hundreds of different characters from across the series that are cool, use different weapons and have unique designs, but all we're ever going to get are the main characters and it's disappointing.
- Kumatora or Duster from Mother 3. Kumatora would be a good way to include different PSI techniques that Ness and Lucas don't cover and I think it would be cool if her Final Smash was PK Ground since that's her strongest attack. Duster, meanwhile, has the kicks and his various Thief Tools that would make for an entirely different moveset that would be nice to see. I don't see either happening, both because Nintendo will never release Mother 3 outside of Japan and because of plot relevant stuff, I don't foresee them actually using Duster.
- Waluigi. I love Waluigi, but Nintendo don't even use him for anything other than sports and party games and they don't seem to like him all that much, so I don't think he'll ever be more than an Assist Trophy.
- One of the protagonists from the Shin Megami Tensei series, most likely either the Demi-Fiend or Nahobino. The Megami Tensei series has been around since the 80s and the Persona franchise branched off from them starting with Shin Megami Tensei: If..., so since we have Joker from Persona 5 as a member of the Super Smash Bros. roster, it would be cool to see someone from mainline SMT included as well. The Demi-Fiend is probably the likeliest since he's pretty visually striking and is one of the more well known characters, though the Nahobino wouldn't have terrible odds either since he's from the most recent game. Anyway, I think they'd have good moveset potential via demon summoning, and each have their own aspects that could make for good moves individually. Unfortunately, since mainline SMT is significantly more niche than Persona, I don't think it'll ever happen. Maybe Jack Frost as a standalone demon could be added to Smash? He appears in both SMT and Persona and is pretty prominent in advertising and has some recognition; it would be cool to see Pyro Jack/Jack O Lantern (and maybe Jack the Ripper) too as a Jack Bros. set, but that might be asking too much.
