Originally Posted by
Zfz
Parry is a great stat when doing mass trash pulls. It's useless against single targets (boss fights).
So don't run a low-parry set when you're mass-pulling. Swap into your parry set please. A 130 Poetic tank with full-parry relic has over 570 parry rating, but swap out all the parry pieces and you will end up with only 370 or so, which will indeed make parry useless.
A WHM holy hitting that mass pull is better DPS than you can ever do with all the DPS gear you can ever have. Your job is to survive well enough to make those Holy casts happen.