Originally Posted by
domzae
I'll take this one (primarily talking from a 3v3 point of view), it's a combination of changes from legion to bfa that end up with a really broken spec in PvP.
Firstly, shadows defensives got gutted with BfA, the biggest one being Dispersion, which had a 50% heal attached to it and was a 1m15s cd. (as opposed to now which is just the 60% damage reduction on a 2 minute cooldown.
Next, so much of shadows damage got shifted out of voidform, so going into voidform only gives you a bit of haste, and access to void bolt. On top of that, shadowform gives 10% damage reduction, which is lost when going into voidform.
And then blizzard changed a pvp talent, edge of insanity, to give 20% damage reduction when above 60 insanity and in shadowform.
The result, is that the most optimal way to play shadow in pvp right now is to sit at full insanity and never enter voidform, focusing on strong utility you bring rather than maximising dps. You literally just don't play half of your spec. Going into voidform is just not worth it unless you *have* to score a kill, else you will get swapped to and probably just die before you get back to edge of insanity.
Edit: To be clear, shadow is pretty good right now in 3s, it has a ton of utility, is quite tanky and does enough damage. it's just not fun to not be able to use your spec's mechanics