I'd argue that MM is at a slight disadvantage against Bowser jr. because of his higher mobility and his mecha koopa ruins the pellet game neutral. He also juggles MM hard. But it isn't too bad based on my past experience.
MM definitely has the advantage on Lucario until about 50% where pellets can't cancel out medium charged aura spheres anymore. His moves are really laggy in the neutral, so it's really easy to punish him with pretty much anything. You can actually bring him to 100% in under a minute if you play it right, guy is pellet and MB fodder. However you have to close the stock early of course. As with all characters, you lose to max aura Luke.
Yoshi has a big advantage imo as his aerials are so fast and have high priority. If he rushes you down, you can't challenge anything. Difficult to keep up that zoning wall and punish game if you're not 100% sure on what Yoshi can and can't do.
With Olimar his pikmin eat everything. He has more damage output than us in the neutral with his pikmin latching on to you, and as a result we can't use most of our projectiles effectively, especially against purples. Smash attacks are too lagless to punish at midrange with grabs which is the best way to pop him in the air for us. Hard to keep Olimar in the air where he's weak.
A good ROB can really outcamp and outpoke us. He can easily keep Megaman at bay with good gyro placement and long range lasers. Also his nair eats pellets, one of his best spacing tools. Not the kind of neutral MM thrives in. He can edgeguard us easily too.
Fox is pretty fast and can utilt us forever. Also lasers. We can edgeguard him effectively, but one that has experience against MM can bait out moves and punish and rushdown Megaman hard.
Toon Link and Link have a notable advantage on flat stages even though pellets clank with everything. MM is forced to go through their wall which can be hard because they can spam all apporaches with projectiles in different directions and defend openings with their aerials. MM has to stay inside of that wall while outside of sword range. It's tough without platforms imo. Bombs eat pellets too. Basically another rob matchup except this time you're fightig someone who keeps screaming at you. But remember: this mostly spplies to flat stages (smashville included!!).
Here's a good video of what I mean. I hate fighting good links/TLs....
Rosa has a strong advantage. At neutral it's about 50/50, but even if you spam crash bombers on Luma, that's about all you can do without being dash attacked. have to spend your time camping while maintaining stage control which is almost impossible because of luma priority and meat shield. Best you can do is bring them to duck hunt where you can camp harder. They can actually spam dash attack and you can do little to stop them. The only time we can really get damage is when Luma is gone, but then again we aren't a rushdown character so it's risky. Once you're in the air, prepare to be juggled forever, she punishes every landing with DA or upsmash or uair. It's a matchup that's 10x more stressful on MM than it is Rosa because you can't punish her as hard as she can to you. Also, her edgeguarding beats ours in this MU.
GW's DA beats pellets, his aerials beat our fair and bair, we can't gimp him or edgeguard him well, and he also has the dreaded bucket. Keeping him in the air is hard too because of his dair and horizontal aerials. His Usmash is really gay, can't do anything other than dodge it because of invincibility (like Mario's) and priority.
I think Roy is a bad matchup. Roy players don't really care about any projectiles we send at them and he really puts pressure on us. Can still try to edgeguard him if you go deep I guess though.
We can actually disrupt a ton of Falcon's approaches with pellets and leaf shield, plus he's insanely easy to gimp. Pellets even beat out falcon kick afaik. You can really make him feel suffocated with pellets. Notable advantage here because he can still rush you down if you mess up.
The top row should say clear disadvantage. Other than that, I agree with the rest of the list more or less.
