I don't get why it's a bad idea, it's literally Mario with a trenchcoat and the Megavitamins are just reskined Fireballs
his unique moves make more sense for Mario
I get that it would probably never happen but I don't really care
Because they aren't reskinned fireballs. They're actually different moves with different effects. And that requires a hard "own slot" alone. The tiniest change is why he has a slot in the first place. Do note he's barely different from Mario in Melee. Part of why he got that slot was just to add more music too.
Basically he was like Dark Pit in Melee with barely any differences, and those differences are 100% why he cannot be a skin. Well, a bit more than Dark Pit, but he's a close comparison to the differences.
It was awful in Project M. They failed to make him correctly. He doesn't have any of his actual unique attributes. He isn't Dr. Mario. He's a bad skin as is. The Fireballs and Megavitamins aren't just sound effects and different textures. They always had unique attributes as is. They don't have the same spin at that point. One has a vastly stronger one(Dr. Mario's spin is actually far closer to Luigi's, being a power attack far less than a combo move). They didn't bother to even make the skin good. You were playing as a poor man's version of Dr. Mario, not the cool one from Melee, and later games, where they properly implemented him. Besides, did they even bother to make the Super Jump Punch with an electrical aesthetic? If not, then I'd call it an utter failure of a skin. It can't have different effects whatsoever, but they can change the sounds/aesthetics to be accurate. You either go all in or you don't bother. There's little point in giving him all these things but still have it done wrong. I appreciate the Project M's team's work, but the skin was not good. Alph is also a pretty bad skin for Olimar, but he 0% unique attributes beyond his personality, and actually legit uses the same moveset.
Besides, the Super Sheet is fine on Dr. Mario because it's not the actual Cape. It's just him using a Doctor-related item in a different way. The Cape was never properly used in Smash by Mario. His Tornado is literally the Cape itself(another proper way to use the Cape as a Down B, mind you).
Dr. Mario does need changes to be closer to being what he is, but he has barely any moves, as I noted.
That would be a passable idea if they kept Doc's drill kick and "so long" throw. But instead they gave him the Goomba Stomp and a made-up back throw. The former is a move that Mario absolutely should have considering that's his main if not only form of unarmed combat in several main games and spinoffs.
Even then, the idea of bringing on a character to represent "the old style" of that character doesn't sit entirely well with me anymore. It would be like if they reworked Ganondorf to utilize more of his sword (albeit with similar functions for the sake of this argument) and then brought on Black Shadow to have his old unarmed moves. I'm pretty sure even you would be against that too.
Ganondorf wouldn't be reworked like that either way. Even the most changed characters still clearly have a similar moveset, just play fairly different despite this. Black Shadow can still come as a Ganondorf clone/Echo(depending how much changed attributes matter like weight) and work fine. Literally, Black Shadow(who does not have Captain Falcon's bodyshape so can't be his Echo period) is excellent to represent the Brawl playstyle.
Dr. Mario is definitely a lot closer to the classic style, but that's not all he represents. He has no reason to use the spin throws because he isn't Mario. Also, those spin throws were from the N64 games, which is more of a modern era than classic, so it's not exactly on the wrong person. Dr. Mario is a heavyweight because he wears more clothing and to make him feel different from Mario. ...Ironically he should be more fit, cause, you know, Doctor.
Though do you have an idea of what way better moves they can give him for a Down B and maybe an Up B? And Electrical Super Jump Punch isn't horrid(though as I said above, if Project M didn't implement at least that, they really did a bad job at making him a skin. It can't be an actual different move effect due to skins 100% being aesthetic, but he's the electrical character logically to Mario's Fire due to the types of things they do. That, and to be fair, Mario & Luigi cemented Mario being able to do fiery punches moreso after Smash attempted that in Melee to help change him up from Luigi).
...The Drill Kick isn't even from an actual Mario game? What game was that from to begin with? Wasn't that specific to Smash? Goomba Stomp, yes. But then again, everyone has something similar with the ability to jump on someone's head. It's not so much as a Goomba Stomp as basically using Luigi's move moreso, where the focus was on "focused hits" instead of combos. It's not really meant to represent that from what we can tell at all. Since that seems a misunderstanding of the move's origins. The move came from Luigi in Melee, where, as I noted, they changed his attacks to be stronger hits with less combo potential to separate him from Mario. Dr. Mario just inherented that attribute since he's not a combo character in For like Mario is. Also, worth noting Doctor Mario is directly using both Mario and Luigi as a base during For. That's why he got the Tornado and not some odd variation on F.L.U.D.D. So you could say the Doc is basically a Mario and Luigi fusion in terms of moveset. He just happens to resemble Melee Mario muchly and thus, is basically akin to the classic playstyle.
It's possibly Luigi's updated Down Air is meant to be the Goomba Stomp, though. And it's a good interpretation of the move, and logical, but it's not that clear, though. Unless I'm missing something about the Goomba Stomp suddenly being a modern move, though?? Cause I remember it from Super Mario Bros. 1, literally jumping on an enemy's head. Also, to be fair, Mario was heavily based upon a Modern game at the time, Super Mario 64, with a few moves from his classic games. Even his throws are from that one. He uses multiple animations/attacks from SM64 in general. Only his Fire Ball and Spin pretty much were related to the classic games outright. Super Jump Punch is just a loose interpretation if him hitting a block underneath, and present in a ton of games, so doesn't really count as being from a strict era. Is it a good interpretation? Eh, no. It's a great move in the sense of "He's the Jumpman!" though?