Did any of these people play Arenas? And outside of RM / RMP / RLS combos?
Awful imbalance, especially season 11. PvE items in PvP, Gurthalak warriors, Unheeded Warning / Vial of Shadows / Legendary dagger Rogues, 1shots everywhere. Rogues in Cata made whole game (especially on PvP realms) unfun for everyone else, they were a huge pain in the ass. Even DKs in start of WoTLK weren't that OP.
Despite all the complaints about BFA / SL arenas, I find Cata seasons (especially Dragonsoul one) all time worst.