Intellect is still your primary stat, it provides you with Spell Power and increases the damage of your spells.
Criticial Strike increases your chance to critically hit with all spells and abilties. Critical Strike is pretty strong for Affliction Warlocks due to the effects of Perdition.
Haste decreases the cast speed of your spells and increases the number of ticks from your DoTs. Haste also scales with pets and quickens the ramp up damage from Agony.
Versatility is a flat-out damage done increase and damage taken reduction.
Sin'dorei Spite can be used in all Warlock Specializations and grants 30% increased damage for 25 seconds after using Summon Doomguard or Summon Infernal. Good legendary for pushing damage checks and offering a strong burst.
Power Cord of Lethtendris causes unstable affliction to have a 25% chance to refund a Soul Shard if there is not an unstable affliction on the target. This legendary is really good on multi target bosses however is also pretty strong on single target.
Streten's Sleepless Shackles causes each enemy afflicted by your unstable affliction to also grant an extra 4% damage bonus. Not that great as unstable affliction is a short DoT however can still be useful.
Best Single Target legendaries
Best Cleave legendaries
Generally any item with high Mastery/Crit/Haste is king when it comes to gearing;
T19 bonuses are pretty strong for Affliction Warlocks too
T19 2 piece bonus is pretty strong as unstable affliction does so much damage as an Affliction Warlock.
T19 4 piece bonus is pretty strong is worth losing quite a lot of ilvl over (40ilvl+)
- Erractic Metronome (Chronomatic Anomoly)
- Whispers in the Dark (Gul'dan)
- Brinewater Slime in a Bottle with either Crit/Haste/Mastery (Helya)
Races are a lot less beneficial than they use to be however the best DPS ones are:
Socket Masterful Shadowruby in all.
You should always use the following consumables to maximize your DPS:
Flask: Flask of the Whispered Pact
Potion: Potion of Prolonged Power
Rune: Defiled Augment Rune
Vantus Runes: List of Vantus Runes