>>53229481>>Chi-Yu is better at Reshiram's niche than ReshiramThis point is where I take issue. Reshiram is a wholly different beast in OU than in Ubers, because there its very-good bulk and decent resistances actually matter and are unique. Chi-Yu is faster and hits harder, sure, but it would be a lot easier to toss Reshiram out into say Heatran to start your offense. Reshiram's "niche" is entirely different if you put it in a different tier, because that's the whole point of a niche: how it fits into said tier.
In the context of Ubers, I think we can all agree that Chi-Yu is the better mon with the more well-defined niche. But that's not because having the extra Speed and Special Attack is better by some immutable Law of Pokemon, it's just circumstantially better because the bulky wallbreaker thing is done better by other mons in that tier.
Chi-Yu isn't too good for OU because it's objectively better than X box legend, it's too good for OU on its own merits.