This is all of my opinion. I'm not claiming anything to be fact that isn't known already. (MK being a beast, for example.)
How about the other reason for temporary banishment?
Banning Meta Knight as to establish a metagame that ISNT centralised around meta knight, and allow the people who are 'swing votes' to consider whether they prefer the competitive game with or without meta knight.
HURRR.
Which will in turn result in either a permanent banishment, or having him unbanned as it doesn't really make a 'better' difference.
So meanwhile, those who are playing MK (top players and otherwise)
must go and focus on some other character because their main is banned for some period of time, or they should just play a new game?
You can't just "ban and unban" as if nothing ever really happened and return to what you have. Let us assume he is unbanned after this. MK would still be MK, yes, but let's say everyone went along with this and played other characters when he's banned. He gets unbanned. Ignoring anything about the metagame since you don't seem to like that argument, he will come back without any tournament play whatsoever.
Without any tournament play, he'll be unranked. He will NOT jump back immediately to S-rank because everyone else at the top will have a huge lead on him. Every character would be "inexperienced" against MK, or less experienced, in the tournament scene because he has been absent. I can imagine that people would still play him during that time he was banned from tournaments, so I can also picture that they'd come back and he'd eventually climb his way back to the top again.
What do you gain out of this? The knowledge of what happens when you ban MK would be nice, but at its expense, you:
- force many players to pick up a new main and/or new secondaries
- force an environment that, according to you, isn't shown with MK centralizing the metagame
- force MK back into a staled environment where many players are not gonna be used to fighting him; if top MKs were still playing along and returned to this, they've probably been keeping their MKs hot outside of the tournament scene and they'd come back and **** lots of tournaments
- force a situation that replicates the current one we're in, except now that MK is back and ****** the tournament scene, people know what it is like without MK
- force a permanent ban of MK
In my opinion, that's how things would turn out
if everyone played along. What would really happen is more people would drop Brawl and nothing worthwhile would get done except for, I don't know, more fun for everyone else... unless, of course, MK wasn't your biggest problem and Marth was, lol.
All of that assumes he's unbanned.
If he's permanently banned from the start, many people would quit this game, so you're either working with a "centralized" metagame or an immediate, much smaller, much weaker metagame of characters that get ***** by the standard tournament pains-in-the-*** and resume to doing something about their worst fights, which may be more in number because of the absence of MK or possibly less in number if many people quit (though eventually that number would rise again because there will always be new players). In the very long run, I am not sure how things would look, though obviously if you compare the world where MK is banned and the one that he isn't, you'd get a drastic change. However, I believe that the absence of MK would make things worse off because I can see the top tier advancing their metagames and one of those characters finding something "gamebreaking", thus placing that character at the very top of the metagame, where it then becomes over-centralized again.
This is all theorycraft, and apparently people on this site abhor it. I would like to never see this poll again myself, and the only way that'll happen is if MK is banned, and if he is banned, he would be permanently banned. This would be my prediction. In the end, I say that if we're gonna ban him, it needs to be permanent and from the start... but I also say that he doesn't get the ban.