I don’t know every class and spec, and I can’t peak behind the curtain, but to me it looks like blizzard is balancing PvP based on average end of match damage meters. Classes and specs which deal large amounts of sustain, spread and pad damage all seem to be awful, where classes that deal all their damage directly are popping off.
While data based balance might seem good from the outside, it’s really just a lazy way to handle a complex problem that requires a much more nuanced take. Which one is better, dealing 10 damage directly or dealing 1 damage ever 3 seconds for 30 seconds? Obviously it’s the 10 direct damage, but if you balance based on end of match numbers the two will appear equal. This method would also ignore opportunity cost, crowd control/disruption, GCD, mobility, hard defensives vs soft defensives, ranged opportunity vs melee opportunity, healing debuffs and even pets (and their uptimes, survivability and opportunity costs). This draws no differentiation between pad damage that is effectively healed for free and damage that actually depletes healer mana, or adds extra pressure to the kill target.
Maybe I’m chasing ghosts, but I’m starting to think the PvP balance changes are based on someone looking at a spreadsheet instead of someone actually playing the game, because they really don’t map onto how the game is actually played. Some specs should be doing more damage than others, while other specs should deal less damage but be way more likely to land an actual kill. For example, Unholy dks should deal more damage than Frost dks, but Frost dks should have higher KBs, Affliction Warlocks should deal more damage than Destruction Warlocks, but Destruction Warlocks should have higher KBs.