If you compare Shadow Priest to other Ranged DPS classes I am struggling to understand what is the niche for this class. Lets compare:
Devastation Evoker/Arcane Mage
A shadow priest has objectively MUCH worse mobility…
Small scale/Large scale AOE…
Single Target DMG…
Survivability…
Furthermore both of these classes bring Lust (as well as Shaman and Hunter), Warlocks bring Brez are tankier and higher dmg profile ST, AOE small and AOE big.
So if you compare mobility, survivability, burst DPS, sustained DPS, ST, AOE 2-8 mobs, AOE 8+… Shadow Priest isnt shining in ANY area, theres NO reason to bring a Priest thats going to do less damage to trash, mid dmg to bosses and be a world harder to heal because their defensives are Dispersion which makes u unable to act, or a 1.5m cd 30% health increase which mitigates less damage than a basic 20% dr.
There have been times where Shadow Priests could look forward to a type of fight be it ST, 2T or AOE and know that at least they were useful in one area. Now you are likely to just lag the Fury/Ret or whatever other class is using a 90iq dps rotation with limited combat keybinds and WA tracking, vs a Shadow Priest where you need to 200iq a 90 parse only to be 9th dmg in the raid behind the tanks wife who rolled a Havoc DH.
edit
Crazy ideas (perma DR, perma cast while moving, perma psychic link in combat)
Inner Will should be a perma % DR on Shadow Priests like an active D-Stance…
Levitate allows you to cast while moving and doesnt drop in combat.
Psychic Link doesnt need DoT’s its just on whatever is red/in-combat. I just wanna dps not worry about dotting adds over here and there.
Maybe a talent that gets rid of the dots and transfers the DPS power to your spells. One thing I noticed about Evoker is dragonrage is so bad the power budget tied up in their 2min CD is like nothing whereas in Priest Void Form is our life.
Small tunings aint gonna do much for this class. @me if you’ve had the absolute mistery of Queen Ansurek heroic. When am I supposed to stop and cast during P1? During P2? Youre either positioning poison spawns, moving out of them, moving into exploding green glob, moving the webs together or moving away from grips… Shadow Priest cannot handle this like classes with a modern game design.