We had Dr. Mario highlighted today. Let's talk about how bad he is in 4 fundamentally. He's quite similar to Mario, but he's lower mobility which makes it harder for him to win neutral and his combo game is worse which more than offsets his extra power to overall make him require winning more exchanges to take a stock than Mario requires which can be effectively translated to him being worse in terms of effective power which means his only upside is meaningless. You're just left with winning fewer exchanges when you need to win more to succeed versus the obvious alternative; what a pointless character to pick. He also has a worse recovery which isn't even a big deal but is just more negative to go along with him not having real upside. The only upside at all is that the very direct power is better if you use a read heavy playstyle, but if you want to play a read heavy playstyle with a plumber style moveset, seriously Luigi is right over there and waiting to actually do that job competently unlike Doc.
We don't really know anything about Doc in Ultimate other than that he has a new dair. In 4, moves that only serve as meteors are mostly bad moves in effect; Doc *really* needs that to be untrue in Ultimate to have a real upside to start with. I could totally see a world where the "minimum tech distance" thing remains true so on-stage meteors are actually consistently useful so Doc could set up offense off that; it's a really important thing that I think Doc needs to go well. I think Doc needs to have less stark of a mobility disadvantage as well; it's the design that he's worse at it, but he's probably too much worse in 4 to be realistically considerable. I hope in general they work harder to give Doc a more unique identity while they're at it; do something like make the pills a lot better when Mario doesn't get comparable buffs to fireballs or something. The thing is that, in a game with a large roster, Doc might or might not be a bad character, but a character who is a worse version of another character is automatically one of the worst possible picks at all levels of play so they really need to think seriously about how to tune Doc to avoid making him the most pointless character in the game two games in a row.