The whole concept of tiers being determined by usage doesn't seem that fair to me, but that's just my opinion. I looked at the data that Smogon collected for the battles on its server, and some of the least-used pokemon could be good in OU. Bronzong, for instance, is a great counter to most OU sweepers, yet it was placed solidly in UU based on the number of people who used it. And that's just one example of many. In light of this, I'd like to discuss how tiers should really be organized.
Should tiers be based on usage, or usefulness?
Should tiers be based on usage, or usefulness?