I'd have to say wit me, I jus like goin against the tide. I main ICs, Link and Roy n I think just about any character has the potential to be a real top tier. Ive seen planety of vids of ppl using lower tiers n beating, not only hi tiers, but top players. such as a G&W beating M2K's fox. Aniki's Link beating Ken's marth, Mewtwo beating Bombsoldier's falco, ect. The tiers list simply infulences ppl to play wit high tiers so dat noone uses the lower ones.
Those vids are pretty old =p
Japan is pretty behind the US in terms of metagame as of present day.
While I agree with you that low tier characters can be played at a high level, I feel like I have to say that the people who have done things like that are incredible good players no matter what character they play. M2K's Pichu could likely beast 90% of smashboards' anything, but Pichu is a terrible character.
The really good thing about melee is that it's flexible enough to allow lower tiers to perform that well. But there are still notable differences in hitboxes, lag speed, priority, versatility, adaptability that some characters have that others don't.
Best example, grab an action replay and turn all characters into wire frames and look at their hitboxes. 80% of Jiggly's moves have bigger hitboxes than pichu's entire body. -__-
Not to mention higher tiers are plagued with gay things like disjointed hitboxes and lagless moves.
Personally I continue to main Samus because I'm aware of how good she can actually be. Just look at what Alukard and Hugs are capable of doing so some of the best players.
I started playing her because Super Metroid on the SNES was too good. :D