Right, so let's lower the standard in a way that makes Usain Bolt's natural ability absolutely meaningless!
Are you suggesting that banning Meta-Knight is akin to say, sticking Usain with a pair of shoes that make him (and by consequence, everyone else) slower?
The way I'm hearing you, you believe that Meta-Knight is the best way for people to flesh out their natural skill, which is why we have the issue of over-centralization.
One of pro-ban's big arguments is that character viability would increase if Meta Knight were to be banned.
In the case of my Usain hypothetical, this would be akin to there being a pair of shoes that adds 1.5 m/s to his running speed, and several other pairs that range in the .9-1.1 m/s second range. Obviously, nobody is going to use the other shoes instead, so we have over-centralization.
This can be applied directly to the data Over-swarm has provided regarding character diversity. In his chart, we see MK has 30% dominance (approximately, I'm going by memory), while most other viable top-tiers are in the 7-9% range. This is why over-centralization is one of the arguments to ban him, so we can enjoy a more diverse, healthy meta-game.
Now that I think about it, there's a real-life example that I can use to back this up. In competitive swimming, there is one type of full body swim-suit that EVERYONE used (Meta-Knight), because of how hydro-dynamic (Strong) it was, and it provided a significant advantage over all other kinds of swimsuits. (characters)
This swimsuit was banned as a result of general distaste, (Particularily Michael Phelps' outcry, which could, in terms of cross-comparison, be likened to Sirlin's suggestion to ban Akuma) and the significant advantages it provided over everything else.
Here's a quote from Double Olympic Gold Medalist Rebecca Adlington that goes along with this:
"I think it's a shame to be honest," the 20-year-old Adlington told BBC Sport. "Swimming always used to be a level playing field.
"I can remember watching when they were just in trunks and 100% textile suits, whereas now it's very, very different.
"The technology has just taken off in the last year, it's come from nowhere. We need to go back to putting rules in place, just to make it a fair playing field for everyone."
This turned into a bigger wall of text than intended, by the parallels are pretty clear here. Sometimes, when things provide too much of an advantage, they have to be banned.