Which brings us back the original question: if you're playing to win, why are you not playing MK?
Not everyone competitive immediately radiates to the Top Tier. Of all the game community's out there, I thought Smash would be the one who effectively knew that rule from the get go-- seeing as how some of the best players here don't always gravitate towards only Top Tier characters.
Look, while a majority will use MK, some people just don't fit his style. They don't like playing him, it's not fun, it's not beneficial, and really-- it's pointless. They just don't like the character all that much. If there are characters they can master, who they can play BETTER than MK, and produce results with-- it's best they go with that one.
It's fairly amateur just to pick a character due to his tier placement. It depends on how the character suits your style of play, your mindset, and the mechanics you play with best. Yun is considered by far the most powerful character in 3S, yet Nuki has dominated 2 years in a row with Chun-Li.
Sure, if you're playing to Win and you can pick up MK well enough, it's best to do so. But if theres a character you're better at using, and you can pick up a strategy against MK's(which you CAN.)-- then you're better off picking them.
That's pretty much all I have to say. Everything else I have about this whole banning thing has already been mentioned. Unless you have a character that clearly cannot be beaten from any standpoint whatsoever-- a character who's disadvantages don't exist(MK has disadvantages, don't kid yourself), and who the game engine caters too on a regular basis outside of the regular ruleset, then that Char is broken. In other words:
Unless you give me an MK with the SNK boss syndrome, or a MASTER HAND like playstyle... he isn't broken. Not by a long shot. He's just easier to pick up as a character, and he's adaptable. Big deal, welcome to fighting games.
That's it. I'm not really in the mood for arguing. Just thought I'd give a respectable $00.02 in.