I helped Panser do a thing for Warlock Changes in 7.0, a part of her Legion Class Series, which you can view below. If you prefer to simply read over the changes yourself I’ve included my version of the write-up below as well.
The most universal difference for Warlocks in 7.0 is that we all now use the same secondary resource system, Soul Shards, instead of each spec having a unique resource.
Draenor perks and a handful of Major glyphs have been removed/baked into abilities and almost all Minor glyphs have the ability to be applied directly to the spell/pet. Most notably the graphics of your demons that used to be only usable when you had Grimoire of Supremacy are now all glyphs usable at any time. There is still a limit of one minor glyph per spell.
Like other classes, there is a more specific shift towards ‘class fantasy’ reinforcing that same idea of what it means to play each spec. There hasn’t been much ability overlap even previously but it’s even more specific now, even going so far as to identifying each spec with a specific pet and dot spells.
All specs share the same main damage CD (Doomguard or Infernal) and had the iconic 10 minute CD reduced to 3 minutes, main mana regeneration source (Life Tap) and main damage reduction CD (Unending Resolve) as well share the same damage reduction passive (Soul Leech).
Affliction Warlocks’ fantasy focuses on damage over time spells and the souls of their enemies. Core abilities have basically remained unchanged for the most part and all retained their DoT components but have had their roles refined and changed. The artifact weapon is a two handed staff called Ulthalesh, the Deadwind Harvester.
Affliction warlocks are masters of shadow-touched powers, but unlike shadow priests—deadliest when pushed to the brink of insanity—these warlocks delight in using fel forces to cause intense pain and suffering in others. They revel in corrupting minds and agonizing souls, leaving enemies in a state of torment that would see them undone in due time. Even the most battle-hardened warriors can be deceived, landing blow after blow against the warlock, only to succumb to their suffering as their very vitality is siphoned away by the dark spellcaster. – Blizzard specifics on Class Fantasy
- Corruption is now just a damaging ability and no longer generates Soul Shards.
- Agony is the new Soul Shard generator and still retains the stacking mechanic it had.
- Unstable Affliction is now the nuking spell of the spec, its’ damage functions in a similar way that Ignite does with Mages and is the main spell that consumes Soul Shards.
- The Artifact ability Reap Souls gives you a damage buff per soul that has been reaped from the enemy, souls are gained by damaging an enemy and are stored around the target until you reap them.
- The Felhunter is the designated pet of Affliction.
Destruction Warlocks’ fantasy focuses on being a master of all things chaos, calling down fire to burn and demolish their enemies. Destruction retained all their core abilities but what they do for you has changed slightly. The artifact weapon is a two handed staff called Scepter of Sargeras.
Warlocks who command the power of destruction favor incantations of pure chaos and aggression in battle. In this regard, they’d find a stronger kinship with fire mages than warlocks of other disciplines—if not for their propensity to make use of magic deemed detestable by all mage orders. The destruction warlock is well-versed in discharging a dizzying array of shadow, fel, fire, and chaos magics upon opponents that rattle souls and conflagrate bodies. They require little motivation for the havoc they wreak, happy to revel in the destruction they cause—thrilled at any opportunity to watch the world erupt in discord around them. Warlocks who command the power of destruction favor incantations of pure chaos and aggression. – Blizzard specifics on Class Fantasy
- Immolate is still the only dot effect for Destruction Warlocks and is a Soul Shard generator per tick of damage it deals.
- Incinerate is now just a normal filler spell doing nothing special.
- Conflagrate is now a main resource generator and no longer decreases cast time of Incinerate or Chaos Bolt.
- Chaos Bolt remains as the resource spender and retains the resource cost of 2 Soul Shards per cast.
- The Artifact ability is called Dimensional Rift which rips a hole in time and space opening a portal damaging your target.
- The Imp is the designated pet for Destruction.
Demonology Warlocks’ fantasy focuses on being a master of demons with the ability to compel demonic powers to aid them. This is the spec that has gone through the most changes and lost a number of core abilities (RIP Metamorphosis). The artifact weapon is an off-hand (and dagger) called Skull of the Man’ari and Spine of Thal’kiel respectively.
By their very nature, demons are leeches on the living universe—but the demonologist has mastered harnessing the power of these malefic beings on the field of battle. Warlocks harvest the souls of their defeated enemies; those specialized in the ways of demonology use this life essence to tap into the Void, pulling all manner of abomination from the chaos of the Twisting Nether. While such a practice is often considered by outsiders to be wicked and reckless, the demonologist maintains absolute control over the summoned creatures. These malignant entities are fully beholden to—and empowered by—the will of the warlock, until banished to the realm from whence they came. – Blizzard specifics on Class Fantasy
- Doom is the ‘only’ damaging over time ability of the spec which deals its’ damage in one lump sum at the end of its’ duration also granting a Soul Shard when it does damage. I say it’s the ‘only’ DoT because it is the only traditional DoT that the spec retained.
- Shadow Bolt is still the main spell for resource generation, main filler spell.
- Hand of Gul’dan was changed to have a summoning effect; for every Soul Shard it uses (1 minimum to 4 maximum) it summons a Wild Imp in return. It is one of two main resource spenders and is essentially just a fancy dot ability.
- Call Dreadstalkers is a resource spender that costs 2 Soul Shards per cast on a 15 second cooldown, it always summons 2 Dreadstalkers per cast. This is the second main resource spender, you can consider this also as a fancy dot ability with a cooldown.
- Demonic Empowerment is a new core ability which when casted empowers all your current demons causing them to have increased haste and health. You want your pets to be empowered as much as possible.
- The Artifact ability is Thal’kiel’s Consumption which drains life from your demons and deals a portion of their combined health as damage to the enemy.
- The Felguard is the designated pet for Demonology.
- The resource system was overhauled so that all specs use the same resource; Soul Shards.
- Affliction is still a master of DoTs, heavily emphasizing on having as many enemies affected by them as possible.
- Destruction is mostly unchanged, retained basically everything about it.
- Demonology received the most changes, emphasizing on summoning and buffing their demons while manipulating their health and damage.