Doctor Tornado and Dair. From my accounts.
Ah, okay, now I have a basis to provide polite and (ideally) helpful insight.
Doc Nado sucks as a recovery move honestly, well, it has commendable horizontal distance and helps his horizontal recovery but his vertical recovery is terrible so...yeah. What Doctor Tornado's actual use is, funny enough, unlike any other Smash game, it is an offensive move. As strange as this was to me, Doctor Tornado actually beats a LOT of moves it probably shouldn't (Sonic's spindash wut, among other things, I've seen it flat out beat Charizard's Up+B from below)
Dair is an interesting case, it's not a particularly good move but its main niche is to bop spotdodges or a roll if you place it right since it has a hitbox upon landing. It's not incredibly good BUT I think it works better for Doc than it does for Mario as it is definitely more of a defensive tool. By this I mean if Doc had Mario's Dair it would probably be worse with him due to his lower jump and worse air mobility not being able to squeeze the most use out of it.
Now that we're back to square one and I know what you're talking about, that's my insight.
I prefer Doc due to his heavier physics and better offensive capabilities once he's in CQC range. I feel like he can do that a bit better than Mario (Killing at lower percents makes Doc's damage sufficient), but again, that's my own opinion. HOWEVER I believe Mario goes in and out a lot better than Doc and struggles less to get inside the enemy's range, but I feel Mario's offensive traits are either too difficult for me or just more difficult to grasp.
Next time, please elaborate on stuff because the statement of "useless moves" looked incredibly blanket and I thought you were talking about his entire moveset. The vibe I got from that entire post was that "Doc is trash just pick Mario" and...well, it kind of sucks to even get that kind of vibe. I mean I think I got it more from the "Why play a ****ty clone honestly" as you say that to the guy with the Dr. Mario main icon under his avatar

.