As always, SIM YOURSELF at https://www.raidbots.com/simbot/topgear since what stats is the best changes all the time based on your character, how much you have of each stat, what the item level difference is between the items, what kind of fight it is. etc.
Generally though, stat priority should be:
Int > Haste > Mastery > Vers/Crit
The biggest difference from previous iterations of Shadow is that Crit has lost a lot of value. From the removal of Hungering Void, to the nerf to Apparition no longer spawning 2 ghosts on crit etc. has devalued crit heavily.
Crit: Chance for spells to do double damage. Causes Shadowy Apparitions to deal 100% increased damage if the Mind Blast, Devouring Plague, Void Bolt or Mind Sear was a Critical Strike. Tormented Spirits has increased chance to proc on Critical Strike.
Haste: Increases spell casting and dot tick speed, reduces the cooldown of some spells and lowers the global cooldown.
Mastery: Increases your damage on the target for each Shadow Word: Pain, Vampiric Touch and Devouring Plague effect that you have active on the target. During Voidform all targets receive the maximum effect.
Versatility: Increases damage and healing done and reduces damage taken.
The best way to calculate stat priorities for your character is to "sim" your characterFind out how to sim
Racials very rarely matter when it comes to DPS. The difference between them has always been close enough that it doesn't matter what you play. So you should look at what other things the races bring, such as Rocket Jump from Goblin, Arcane Torrent from Blood Elf, Spatial Rift from Void Elf, Shadowmeld from Night Elf, Stoneform from Dwarf etc.
I will always say Goblin if you’re Horde because the added mobility from Rocket Jump is just impossible to compete with.
And Void Elf/Night Elf/Dwarf if you’re Alliance.
If all you care about is DPS, then it is Orc or Troll for Horde, and Human for Alliance.
Rings: Devotion of Haste or Devotion of Mastery
Chest: Waking Stats
Weapon: Sophic Devotion
Bracers: Devotion of Speed
Cloak: Graceful Avoidance or Homebound Speed
Legs: Frozen Spellthread
Primalist Gems (Unique to 1):
- Fierce Illimited Diamond: Primary stat and haste
- Quick Ysemerald: Haste
- Keen Ysemerald: Haste and Mastery
Food: Sizzling Seafood Medley or Grand Banquet of the Kalu’ak
Potion: Elemental Potion of Ultimate Power
Healing Potion: Refreshing Healing Potion
Phial: Phial of Corrupting Rage (if you have 75% or higher uptime) otherwise Phial of Tepid Versatility
Weapon Rune: Howling Rune
Augment Rune: Draconic Augment Rune