I've seen the best DK players in the world lose to people that don't main Dedede. Matchup Experience will only go so far, it's entirely possible to still lose a matchup where your character has the disadvantage but you also know a LOT more than your opponent. Knowing a lot about a disadvantaged matchup will not change the fact that your character is... disadvantaged lol.
I would disagree. Most of the best characters in the game have insane frame data/options compared to the rest of the cast. The only Top tier character IMO that really has a "mental" advantage on people is Wario since a lot of people still don't fully grasp how well he can move. That or possibly Diddy.
If you look closer at MK's frame data, you would see more of a "mechanical" advantage. I'll give you some examples:
Grounded Shuttle Loop invincibility frames start at frame 5 (lasts til frame 8 I believe). This means that if you are at a standstill with another character and MK initiates Shuttle Loop at the same time that the other person initiates a grab, that MK will be invincible and avoid the grab while hitting back with his Upb.
His Bair, when autocancelled right, has a FRAME ADVANTAGE against the opponent. That means MK can Bair someone's shield AND ATTACK THEM AGAIN before they can move (they can attempt to Shield grab or Upb OOS, but they only have 4 frames to catch you assuming they move frame perfect, which means that even if you were in range for a shield grab that MK could spot dodge it).
But of course, you
probably already knew this and decided anyways to say MK doesn't have that big of a in game advantage over people.
*I'm not posting that as a "Ban MK" or "Keep MK banned" message, I'm just bothered when people basically say or suggest "Lol MK's not that good you just need to get better". It's one thing if you don't think MK is broken, but to honestly think he doesn't have that big of an advantage over the rest of the cast when talking about frame data or hitboxes? Why else is he clearly the best character in the game if it's not because he has the best options? lol.*