I’m not saying Disc is causing problems, just that it’s a historically weird spec to balance in reference to the person I replied to.
If anything is to “blame” it’s Blizzard being lazy and uninspired with Priest design in general. PI is a good example: I’d rather they just delete the spell altogether OR make it a Disc or Holy only spell, then give Shadow some other unique/useful utility. I think PI, while fun in a lot of ways, is bad for the class/game.
But instead of actually giving Priests unique, spec specific utility based on their roles, Blizz was just like “Yea, here’s PI and Twins, and also a PI tax”. It’s the same thing with interrupts, knockbacks, etc. Instead of coming up with a way to make priest utility useful and relatively unique (or instead of even just giving us generic spells so we’re on par with other classes) they just deleted all our utility and said they like that for the class.
Also, Shadow was fine before Legion. It’s been redesigned a billion times because Voidform was horribly designed, and it’s taken them 6 years to realize maybe just removing it was the right move (but they won’t, because people creamed themselves over the .05% of moments where it was godlike in legion)