In methodology, there’s a concept called “garbage in, garbage out.” That means if one uses data that is not representative to the population being studied, or the assumptions in one’s modeling are incorrect, then the results will be useless.
I don’t feel like teaching/arguing about statistical modeling and methodology today, so I’ll just leave it at assessing the balance of a PvP server via a voluntary raid logging site for end-game PvE content is not going to answer the question you are asking with any sort of validity.
That said, historically the closest balanced servers have been RP-PvP servers–a trend that was holding true in Classic before the census add-ons were taken down. That leaves you two choices: Grobbulus and Deviate Delight. Someone wanted to play on an east coast server would ideally choose DD, but that has to be balanced against the fact that it’s currently a low pop server.