ADHD, I apologize in advance if I'm not a high seated SBR-B member, or a respectable enough smasher.
Long post ahead, and no TL;DR, sorry.
I'm not going to argue with you that Metaknight isn't beatable. I understand that he IS beatable, and it has been demonstrated by many of the good players here in Smashboards, as well as yourself.
I will argue with you however, on how Metaknight potentially breaks the competitive aspect of Brawl.
1. Metaknight will never be at a disadvantaged position: Metaknight will pretty much always have the upper hand. Metaknight's most even matchup is against himself. His second most even matchup is against Diddy, Snake, Wario, Falco, IC's, and some others I'm probably forgetting. However, from the ones I've written, it's officially 55:45 on MK's favor, according to both MK's Matchup discussion thread, and the individual character's matchup thread. In other words, both parties agree that MK has the slight advantage.
Stage wise, it is said that MK does generally well on all stages. The only way to counterpick an MK is not getting a stage that is BAD for MK, but much rather a stage that is good for X character you are using. All this really means is that you aren't making MK worse, you are just helping yourself. No other character can say this for themselves other than MK. Snake/Diddy both suffer from Rainbow Cruise since the stage scrolls and mines/bananas will scroll and disappear along with the stage.
Anyways, what I'm trying to say is that it's pretty much impossible to put MK at a disadvantaged position. The most it'll ever go is probably even, but never at a disadvantage. However, let me make myself clear though. I don't think this is a good enough argument alone to ban MK, since
even at a disadvantaged position, it is STILL possible to overcome a Metaknight.
What I want to say with this argument is that what's the point of playing a game if someone will pretty much always have the upper hand? It's like playing a game of basketball in which Team A always starts with the ball, and the only way Team B can score is if they steal the ball from Team A and score a point. Winning isn't impossible, but it's really hard, and there's NOTHING you can do to make the game more even or balanced. And just like that, the competitive aspect of the game will turn to trash, everyone will just CP Metaknight to get the game even. This leads me to my second argument:
2. Metaknight is over-centralized: Actually, I'm writing a post in another tab to further detail MK's dominance in tournament attendance and results. I'll post the link later, when I finish the post.
3. Metaknight can play gayer the rest of the cast: He's probably the best and most used character to plank with that I've ever witnessed. He's virtually unstoppable when he starts to plank, and I know this not because Smashboards told me, but because I've dealt with planking MKs myself. I am fully aware that there is a way to limit planking, and that is to set a grab limit. However, there are 2 problems with setting a grab limit.
A. There is no official grab limit yet: If there is, then just correct me and I'll understand, but since there isn't, it's completely up to the TOs to add one. If they don't add a planking limit, then MK can easily abuse that limit, along with any other character (although MK is known to do it better, and more often).
B. The rule won't always be enforced: I'm not sure if you guys know Excel Zero and Ling Ling from Puerto Rico, but if you have, then you've probably heard good things from them, like how they are a
really good Brawl team. The reason why I'm bringing this up is because there was a situation in Pound 4 in which Team PR got planked by KSizzle+Zucco. When they reported it in to the TOs, they said that there was no planking limit. When Team PR showed the TOs the
official Pound 4 ruleset, it was apparently ignored and Team PR got eliminated.
Puerto Rico left feeling cheated, and because of that event, Brawl in Puerto Rico is almost dead. Which leads me to my last argument....
4. Metaknight will make Brawl die: Metaknight is predicted to follow the same steps as
Jin Kazama in Tekken 4. Actually, I lied. It's technically not a prediction since it's already happened here in Puerto Rico. Metaknight left us with such a bad taste for Brawl that a great portion of the Brawl community here quit (By the way, the Excel Zero/Ling Ling situation isn't the only MK related issue that happened to us). It
REALLY sucks though because I'm part of the small portion that still wants to play, but now there's no competition here, and if I go to the states (hopefully for Apex), my competition will probably be Metaknight.