This video was made to be an example for this discussion.
I was Charizard. Zonez, a notable Anther's Ladder MK main, was MK.
You guys are pretty on-point with the idea that if Charizard walls MK out, MK can't get into his extreme advantageous state. MK's neutral isn't horrible, in fact MK's Rosalina's worst MU because of how easily he punishes Rosa's neutral, but he lacks the tools to throw up a solid defense so his defense becomes either his offense or excellent stage movement. MK excels at getting in and keeping up pressure and Zard excels at walling out and keeping stage control so this becomes a MUs of extremes where MK & Zard fight for stage control then go ham on the other when they get it.
In neutral, Zard has to watch out for 4 moves in particular: Dash Attack, Dash Grab, Up-Tilt, & F-Smash. The first 3 moves are MK's combo-starters. That's where most of his damage is going to come from. He can net upwards of 40-50% off true combos alone. MK's F-Smash comes out the first frame after he releases his charge (frame 24 otherwise) and has only 18 frames of cooldown which makes it safe on shield. The move is pretty safe to just spam and Zard shouldn't try to punish it with anything but Flamethrower or a very well-timed Dash Attack. Zard dies
mid-stage at 90% from the
sourspot (the tip) alone with no rage. I have no problem calling MK's F-Smash the stupidest F-Smash in the game; disjointed,
Ganondorf-level powerful, and safe on shield. At high-percent, it's dangerous for Zard to overcommit to Jabs or Flamethrowers because Dimensional Cape Slash is a very real threat and MK will likely try to dissuade you from using Flamethrower by faking you out with Cape. Always be on-guard against it.
Zard just has to play a solid spacing game with Jabs, Flamethrower, & D-tilt and punish anything he can as hard as he can because MK has to approach becaus ehe can't defend against Charizard's approach. You can grab MK after his Dash Attack if you know it's coming, the timing is just really strict. MK as the same DA as Falcon but it has slightly less lag. To punish, you have to turn around and grab immediately after dropping shield if MK crosses-up with it. I've had it done to me before so I know it's doable. Just abuse the fact that MK's grounded approach options are super limited (Dash Attack & Dash Grab only) and Zard can bat his aerials away with his own SH F-Air or Up-Smash (frame 6 Up-Smash so godlike against MK's D-Air pressure). Flamethrower is GOAT all the time.
If Charizard gets caught in the air, that could be his stock and even as low as 40%. MK's Up-Air combo KOs are a huge X-factor in this MU. If you DI the first hit of aerial Shuttle Loop up and toward MK, the 2nd hit of aerial Shuttle Loop may not connect similar to ZSS' Up-B. There is a sweetspot however that is questionably guaranteed but positioning MK to land it before a character can air dodge away is very tricky and honestly dependent on how you DI the Up-Airs. Also beware of Up-Air fake-outs. Some MKs (like me) will instead of going for Shuttle Loop at the end of a low% Up-Air chain will wait for an air dodge and Mach Tornado you for a possible extra 23% (yes Nado does 23% in this game). Nado is also used as a mix-up just like it was in Brawl. If MK looks like he's going to land beside you without an attack because you shielded his aerial pokes, he may Nado just before he lands and you drop shield to grab or punish. Exactly how it was used in Brawl. It eats Shields like nothing else tho so be wary of that. If you have less than half shield left, MK may go for raw Dimensional Capes or Nados to attempt to break your shield.
If you're being juggled, I would advise you to go for ledge if you can. MK has no aerial that beats Flare Blitz armor so Zard gets a free ledge at the cost of 5% of course. If you can read MK well tho, you can land with N-Air, Flamethrower, or even Rock Smash like always. Just know he's always looking for an Up-Air, Up-Tilt, Grab, or Dash Attack when you try to land. Maybe an F-Smash but we Rock Smash those for big damage.
I'd be willing to sign on a
55:45 's favor. Zard doesn't have to get nearly as close to MK as the rest of the cast to pressure him so MK's tilts and most notable F-Smash become non-factors and if MK gets close enough for those moves to matter, Jab & D-Tilt bats him back out if we don't grab him first. Up-Throw KOs MK very early and he can't even stage CP Zard because MK's best stages (Halberd, Delphino, Dream Land, & Duck Hunt) all make Zard's Up-Throw even more deadly. However do not underestimate MK's Dash Attack, Dash Grab, and juggle game. One bad read on Charizard's part can cost him half his stock. MK's crazy advantageous state is the only reason I don't quite think this MU is
60:40 (but I'd still probably sign on that too); MK can invalidate Zard's hard work in one swift motion.