I believe that calling Dr. Mario the worst is incredibly misinformed and generally focuses on his negative traits in a vacuum. Most reasons provided involve recovery and speed, and while I agree those are what put him in the low tiers for me, I see a few significant things holding him out of the bottom.
- Megavitamins are actually a very good projectile. No, really, despite the lag they are very diverse and let you do neat stuff and force approaches in various ways thanks to their extra bouncy properties. SH Megavitamin covers different options than a full hopped pill.
- His combo game is stellar but not Mario's, HOWEVER his strings are more damaging as a whole. The damage trade off overall isn't super worth it but it is notably better than Mario's.
- He has more kill moves in his kit, and while this seems small and it would be small, the way move staling works in this game makes this very important. Unlike Mario who usually wants a fresh USmash ready for a kill, Doc has a bunch of options. FSmash, no matter how it's spaced, kills at very low %s compared to Mario's (I believe 10% earlier which is actually REALLY good). DSmash is also stronger (kind of negligible but whatever), and Up+B adds to his kit of very diverse kill options. Up+B OoS being a kill move is also unbelievably amazing and nobody mentioning it makes me upset. You do realize that no other Up+B OoS can kill as reliably as Doc's barring Luigi's sweetspot, right? Factoring in rage Doc's Up+B turns into an atomic reactor.
- Frame data. His slow movement doesn't always let him optimally squeeze this stuff out, but it's there. When the enemy is in Dr. Mario's world (i.e. disadvantage or up close where you want them) they have to deal with Mario's strong startup frames but with slightly more damage.
- His MU with Dedede is hardly that bad, even Ganondorf isn't bad. Both of them I believe he does either equal or better than Mario on-stage because of megavitamins. Megavitamins reflect gordos and are, again, great for diverse options and D3 is a big fat target. He can inhale them but that makes him lag in place which is an entertaining punish to go for. Ganon has it even worse vs. Megavitamins, you'd think "Man Wizard's Dropkick" but the vitamins bounce at a nasty angle where Ganon can't reliably run under them when thrown properly, and Wizard's Dropkick will run into them as its trajectory is much more suited for straightforward projectile.
- Doc's cape can instantly ledgesnap AND reflect a projectile at the same time. Incredibly useful. It also has more applications on-stage if you're jumping and make a good read.
- Doc Tornado is an incredibly good move. Its priority is absolutely absurd. M@v, from his experience with Dabuz, believes that Doc Nado effectively shuts down a lot of Olimar's options. I've seen it beat Zard's Up+B from BELOW Doc. IDK what's up with it but we need to utilize it more.
There's so much more I could talk about but nothing tells me he's the worst in the game. Do I think he's below average? Probably. Highest I'd put him is like, 34-38, lowest would be 40-42 overall. It's easy to think he's unviable but I really don't agree with that logic and I think this is a result of really aggressive early metagame. Doc can't really DO aggressive play so maybe once it evens out we'll get a more solid perspective on this. Don't get me wrong, I don't disagree with the notion of him being below average, but I really don't think worst in the game either. I also blame this on the fact that a lot of people have come to the crossroads that having not great MUs vs. the top tiers makes you immediately awful. I don't think he has a single unwinnable MU in this game (maybe there's one but I'm not really feeling that way atm).
Wall of Medicine over.