After reading the arguments through, I have come to the conclusion that Meta Knight should be banned just like some stages are.
But as the stages that are banned, if both players agree to play on said stage, you may play on it. Now putting this rule for Meta Knight will allow us to play him if both players agree to use him if they want to. I am a Meta Knight player, I used to main him - but reading the arguments for the ban, reading the facts, he simply is armed to the teeth with attacks to make him shine in any match.
Speaking of stages, it is said that Meta Knight does not have a lot of stages on which he plays bad on, which makes it even harder to choose a stage/character combination to actually defeat a Meta Knight.
Match ups are the main factor since no character is able to put an advantage over him at all. Snake does have bad matchups (according to the Snake boards: D3 and Olimar to name two). This does not mean that the game should be played like a Rock-Paper-Scissor game.
The game has been out for over a year now, which means that we should now have an idea of the main techniques there are to learn, making research almost hopeless when thinking of a strategy to defeat said character.
Please ban him, but for all the Meta Knight mainers - make it quick and painless.
Note: I have by accident voted against the ban, but in the long end - I think Meta Knight will be banned because of before mentioned arguments.