I think it's one of the few outdates mechanics still left in the game
it's just an old archaic RPG element that has no place anymore in the game.
it's sole purpose right now is nothing but to frustrate the shit out of melee dps.
it's not even about "bad melee hitting the boss from the front"
on some bosses you have to do that, and even when you dont when the boss just gets turned around for a second and ends up parrying a crucial ability it's devastating and not fun at all
not to mention completely random.
I think it should go away, it really has no place in the game anymore.
I didnt mind it in vanilla/TBC it was fine then and made sense for the type of game wow was back then. back then if the boss parried an ability you went "oh well a little dmg loss"
now when he parries a cooldown like DFA/kinsbane/colossus smash etc you might as well just stop cos your whole fight is fucked.
but it doesnt work anymore.