In organised BG with set sides a tank is fine and mobility is fine. The issue comes to Random BG’s when you have a DH in Vengeance Spec that has 1.1 Million health (i.e mythic raid geared generally) it’s retarded for anyone to bring them down.
DH heals didn’t get nerfed at ALL they heal a tonne through Leech and it’s BROKEN in so many ways in PvP. When you have a Class that can in tank spec out DPS most DPS and Heal passively while just doing their standard DPS rotations it’s not even close to being balanced. At least most other tanks have to use some kind of cooldown or ability to keep themselves alive. Not the DH they might use a Meta once in a Blue moon but honestly when you see a DH at 30% health with 5 - 6 DPS smashing them and not a single healer on them yet they miraculously in the next second are 100% health again and you then can’t drop them below 80% due to sustained leeching.
Basically I DH, Monks, Druids should not be allowed to Q or change to tank spec in Flag carrying Random BG’s if it’s premade groups for rated then go for it but in the casual game it’s broken sadly