Allowing people to only CP neutrals if they are MK, and/or allowing the player to have no bans for CPs if they choose to play as MK are GOOD IDEAS.
What forces us to ban him outright?
In fact shouldn't we do everything in our power to not ban him outright?
Surgical changes are
bad.
Think of it this way:
Metaknight is inherently changing aspects of the game as a good character on his own. MK has shaped the tier list. The
current status quo are the people that say "just make him play on starters" because
those are the characters that do best on starters. Doing so doesn't change much, if anything, about the game itself. It solves the problem in a half-***** way by telling everyone that isn't going to have a great match on a starter "tough" and just doing what you can to make the second best players better.
Doing this is pretty silly. Not only do you only help those closest to the top, but there's no reason why you can weaken MK but not strengthen, say, Ganondorf.
Making small changes attempting to "fix" a problem like this doesn't work. Every attempt to do so has failed.
You ultimately have two destinations:
1. Messing up and not weakening MK enough
2. Weakening MK enough so that he can be beatable by X character
Why do that? You can't win unless you've weakened MK to a ridiculous margin, and that isn't really fair or controllable.