It's quite interesting that people did hard calculation on parry. It has also been noted that more and more tanks did forgo parry for other stats back in 2.x, especially during the zeta period (crit/det kings). Horrible scaling/RNG and to also think that it doesn't have 100% uptime for the harder contents (tank swaps etc), quite the abysmal stat to stack.

TLDR: parry sucks, BREAKING NEWS. /s