@Dylan...
I said you DO have to practice with whatever character. But you still missed the point. It is undeniable that it is easier to play Sheik than Bowser. Fact. And think about what you're even saying, dude! You say tiers are there; they're inevitable, and then you say that you have to practice equally no matter what. Well, the whole idea of tiers is that, one will always have a higher potential than the other. So it's NOT all about practice, which was my entire point.
And yes, tiers are made by the game designers. Do you think that when we buy the game we reprogram it so that some characters have advantages over others? No. We simply use what the game mechanics give us. Now, whether tiers are intentional that's another story. I believe that tiers are just a lack on the programmers part to correctly balance the game. I don't deny that they won't always exist, but the point is that Melee has SUCH extremes that it was pitiful.
And lastly, you really don't need to look at any evidence other than this; so I will emphasize it: you can tell how balanced the game is by what the character usage spread is. Melee was very skewed, as easy proof that you could give me one, maybe two good Mewtwo players and a list as long as my arm of good Fox players. The 64 is hard to tell this because competitive play wasn't near what it was for Melee, but the spread was a lot better. There were more Pikachu and Kirby players, for sure, but the spread was a lot better than Melee (and not just because of less characters).
Anyway, that's all I have to say. If you read nothing else, just read this, that you can tell how balanced the game is by how even the distribution of character use is. I expect a more balanced game. Tiers may be inevitable to some degree but not to the extremes that they were in Melee.