An Overview of Warlock Class Changes in the War Within Pre-Patch

Lifeblood now grants 4% Leech (was 7%).
All talent trees have had many talents move locations or have had their pathing updated.
New Talent: Pact of Gluttony — Healthstones you conjure for yourself are now Demonic Healthstones and can be used multiple times in combat. Demonic Healthstones cannot be traded.
New Talent: Swift Artifice — Reduces the cast time of Soulstone and Create Healthstone by 50%.
New Talent: Demonic Tactics — Increases melee and spell critical strike chance for you and your summoned demon by 2%.
Fel Pact has been redesigned — Fel Domination cooldown is reduced by 60 seconds and is now a 1-point talent (was 2).
Fiendish Stride has been redesigned — Reduces the damage dealt by Burning Rush by 10%. Burning Rush increases your movement speed by an additional 20%. Now a 1-point talent (was 2).
Soul Leech is now a talent (was learned at level 10).
Mortal Coil has a new visual effect.
Soul Conduit is now a 1-point talent.
The following talents have been removed:

Grimoire of Synergy
Inquisitor's Gaze
Summon Soulkeeper
Profane Bargain

Affliction Warlock Changes in the War Within Pre-Patch

New Talent: Cunning Cruelty — Malefic Rapture has a chance to trigger a Shadow Bolt Volley, dealing damage to 5 enemies within 10 yards of your current target.
New Talent: Summoner's Embrace — Increases the damage dealt by your spells and your demon by 3%.
New Talent: Death's Embrace — Increases Drain Life healing by 30% while your health is at or below 35% health. Damage done by your Agony, Corruption, Unstable Affliction, and Malefic Rapture is increased by 10% when your target is at or below 35% health.
New Talent: Relinquished — Agony has 1.25 times the normal chance to generate a Soul Shard.
New Talent: Improved Shadow Bolt — The cast time of Shadow Bolt is reduced by 15% and Shadow Bolt deals 20% increased damage.
New Talent: Volatile Agony — Refreshing Agony with less than 10 seconds remaining deals Shadow damage to its target and enemies within 10 yards.
New Talent: Summoner's Embrace — Increases the damage dealt or life drained by your Shadow spells and your demon by 3%.
New Talent: Malediction — Increases the critical strike chance of Agony, Corruption, and Unstable Affliction by 10%.
New Talent: Contagion — Critical Strike damage dealt by Agony, Corruption, and Unstable Affliction is increased by 20%.
New Talent: Cull the Weak — Malefic Rapture damage is increased by 8% for each enemy it hits, up to 5 enemies.
New Talent: Oblivion — Unleash wicked magic upon your target's soul, dealing Shadow damage over 3 seconds. Deals 10% increased damage, up to 30%, per damage over time effect you have active on the target. Costs 2 Soul Shards. 45 second cooldown.
New Talent: Improved Haunt — Increases the damage of Haunt by 35% and reduces its cast time by 25%. Haunt now applies Shadow Embrace.
New Talent: Malign Omen — Casting Soul Rot grants 3 applications of Malign Omen. Your next Malefic Rapture deals 20% increased damage and extends the duration of your damage over time effects and Haunt by 2 seconds.
New Talent: Malefic Touch — Malefic Rapture deals an additional Shadowflame damage to each target it affects.
New Talent: Infirmity — The stack count of Agony is increased by 4 when applied by Vile Taint. Enemies damaged by Phantom Singularity take 10% increased damage from you for its duration.
New Talent: Improved Malefic Rapture — Reduces the cast time of Malefic Rapture by 10/20% and increases its damage by 5/10%.
New Talent: Ravenous Afflictions — Critical strikes from your Agony, Corruption, and Unstable Affliction have a chance to grant Nightfall.
New Talent: Perpetual Unstability — The cast time of Unstable Affliction is reduced by 20%. Refreshing Unstable Affliction with 8 or less seconds remaining deals Shadow damage to its target.
Siphon Life has been redesigned — Corruption deals 20% increased damage and heals you for 5% of the damage dealt.
Kindled Malice has been redesigned — Malefic Rapture damage increased by 4/8%. Corruption damage increased by 10/20%.
Malevolent Visionary has been redesigned — Increases the damage of your Summon Darkglare by 70%. When Darkglare extends damage over time effects it also sears the target for Shadow damage.
Shadow Embrace has been redesigned — Shadow Bolt/Drain Soul apply Shadow Embrace, increasing your damage dealt to the target by 4%/2% for 16 seconds. Stacks up to 2/4 times.
Malefic Rapture is now learned at level 43 (was a talent) and deals Shadowflame damage.
Relinquished now causes Agony to have 1.10 times the chance to generate a Soul Shard (was 1.25).
Volatile Agony now deals reduced damage beyond 8 targets.
Haunt damage increased by 230%. This change does not affect PvP.
Dragonflight Season 4 class set bonuses have been updated to the Dragonflight Season 1 class set bonuses:

2 Set Bonus — When Agony grants you a Soul Shard, you have a chance to gain Cruel Inspiration, increasing your haste by 12% for 6 seconds.
4 Set Bonus — Cruel Inspiration also grants 2 charges of Cruel Epiphany, up to 5 charges. Each charge of Cruel Epiphany increases the damage of your next Malefic Rapture or Seed of Corruption by 40%.

The following talents are now 1 point:

Xavius' Gambit
Focused Malignancy
Withering Bolt
Improved Malefic Rapture

The following talents are now 2 points:

Withering Bolt

The following talents have been removed:

Pandemic Invocation
Sow the Seeds
Soul Swap
Doom Blossom
Dread Touch
Soul Flame
Agonizing Corruption
Seized Vitality
Soul-Eater's Gluttony
Grand Warlock's Design
Grim Reach
Haunted Soul
Inevitable Demise
Empowered Unstable Affliction

Demonology Warlock Changes in the War Within Pre-Patch

New Talent: Summon Shadowcaster — Increases the damage of Hand of Gul'dan by 20% and Demonbolt by 10%.
New Talent: Pact of the Ered'ruin — When Doom expires, you have a chance to summon a Doomguard that casts 5 Doom Bolts before departing. Each Doom Bolt deals Shadow damage.
New Talent: Mark of Shatug — Your Summon Vilefiend becomes Summon Gloomhound and learns the following ability: Gloom Slash – Tooth and claw are drenched in malignant shadow magic, causing the Gloomhound’s melee attacks to deal Shadow damage over 6 seconds. If this effect is reapplied, any remaining damage will be added to the new Gloom Slash.
New Talent: Flametouched — Increases the attack speed of your Dreadstalkers by 20% and their critical strike chance by 15%.
New Talent: Rune of Shadows — Increases all damage done by your pet by 4%. Reduces the cast time of Shadow Bolt by 25% and increases its damage by 40%.
New Talent: Demonic Brutality — Critical strikes from your spells and your demons deal 4% increased damage.
New Talent: Fiendish Prowess — Increases the attack speed of your primary demon by 25%.
New Talent: Improved Demonic Tactics — Increases your primary Felguard’s critical strike chance equal to 30% of your critical strike chance.
New Talent: Mark of F'harg — Your Summon Vilefiend becomes Summon Charhound and learns the following ability: Infernal Presence – Cloaked in the ever-burning flames of the abyss, dealing Fire damage to enemies within 10 yards every 1 second.
New Talent: Shadowtouched — Wicked Maw causes the target to take 20% additional Shadow damage from your demons.
New Talent: Foul Mouth — Increases Vilefiend damage by 20% and your Vilefiend’s Bile Spit now applies Wicked Maw.
New Talent: The Houndmaster's Gambit — Your Dreadstalkers deal 50% increased damage while your Vilefiend is active.
New Talent: Blood Invocation — Power Siphon increases the damage of Demonbolt by an additional 25%.
New Talent: Fiendish Oblation — Damage dealt by Grimoire: Felguard is increased by an additional 10% and you gain a Demonic Core when Grimoire: Felguard ends.
New Talent: Doom Eternal — Demonic Cores reduce the duration of Doom by an additional 2 seconds.
New Talent: Impending Doom — Increases the damage of Doom by 30% and Doom summons 1 Wild Imp when it expires.
Doom is now passive and has been redesigned — When Demonbolt consumes a Demonic Core it inflicts impending doom upon the target, dealing Shadow damage to enemies within 10 yards of its target after 20 seconds. Damage is reduced beyond 8 targets. Consuming a Demonic Core reduces the duration of Doom by 2 seconds.
Fel Invocation has been redesigned — Soul Strike deals 20% increased damage and generates a Soul Shard.
You now have a 35% chance to generate a Demonic Core from your summoned Dreadstalkers when they fade (was 100% chance).
Summon Vilefiend cooldown reduced to 30 seconds (was 45 seconds).
Summon Summon Demonic Tyrant cooldown reduced to 1 minute (was 1 minute and 30 seconds).
Your Felguard now charges its target when using Soul Strike.
The Houndmaster's Stratagem has been renamed to Wicked Maw and its icon has been updated.
Dread Calling and Grimoire: Felguard icons have been updated.
Dragonflight Season 4 class set bonuses have been updated to the Dragonflight Season 1 class set bonuses:

2 Set Bonus — Demonbolt and Felstorm damage increased by 20%.
4 Set Bonus — Demonbolt has a chance to make your next Hand of Gul'dan instant and deal 150% increased damage.

The following talents are now 1 point:

Imp Gang Boss
Umbral Blaze
Pact of the Imp Mother
Dread Calling
Demonic Brutality
Flametouched

The following talents have been removed:

Demonic Knowledge
Nether Portal
Ner'zhul's Volition
Gul'dan's Ambition
Stolen Power
Heavy Handed
Fiendish Prowess
Shadow's Bite
Infernal Command
Fel and Steel
Summon Shadowcaster
Malefic Impact
Cavitation
Grand Warlock's Design

Destruction Warlock Changes in the War Within Pre-Patch

New Talent: Devastation — Increases the Critical Strike chance of your Destruction spells by 5%.
New Talent: Emberstorm — Increases the damage done by your Fire spells by 2/4% and reduces the cast time of your Incinerate spell by 10/20%.
New Talent: Decimating Bolt — Hurl bolts of decimating magic at your target, dealing Shadow damage and increase the damage of your next 3 Incinerates by 40%. Decimating Bolt’s damage, and the bonus to Incinerate both increase as your target’s health decreases.
New Talent: Summoner's Embrace — Increases the damage dealt by your spells and your demon by 3%.
New Talent: Indiscriminate Flames — Backdraft increases the damage of your next Chaos Bolt by 5% or increases the critical strike chance of your next Incinerate or Soul Fire by 35%.
New Talent: Blistering Atrophy — Increases the damage of Shadowburn by 20%. Shadowburn always critically strikes a target that is at or below 30% health.
New Talent: Fiendish Cruelty — When Shadowburn fails to kill a target that is at or below 30% health, its cooldown is reduced by 5 seconds.
New Talent: Demonfire Mastery — Increases the damage of Channel Demonfire by 30% and it deals damage 35% faster.
New Talent: Improved Chaos Bolt — Increases the damage of Chaos Bolt by 10% and reduces its cast time by 0.5 seconds.
New Talent: Avatar of Destruction — Consuming Ritual of Ruin summons an Overfiend for 8 seconds. Overfiend generates 1 Soul Shard Fragment every 0.5 seconds and casts Chaos Bolt at its summoner’s target, dealing Chaos damage.
New Talent: Dimension Ripper — Incinerate has a chance to tear open a Dimensional Rift or recharge Dimensional Rift if learned.
New Talent: Flame Rift — Dimensional Rift can now summon a powerful Flame Rift.
New Talent: Lessons of Space-Time — While you have a Dimensional Rift open, all of your damage is increased by 5%.
New Talent: Unstable Rifts — Bolts from Dimensional Rift deal 25% of damage dealt to nearby enemies as Fire damage.
Ruin has been redesigned — Increases the Critical Strike damage of your Destruction spells by 5/10%.
Inferno has been redesigned — Rain of Fire damage is increased by 20% and its Soul Shard cost is reduced by 1.
Decimation has been redesigned — Your critical strikes have a chance to reset the cooldown of Soul Fire and reduce the cast time of your next Soul Fire by 80%.
Chaos Incarnate has been redesigned — Chaos Bolt, Rain of Fire, and Shadowburn always gain at least 70% of the maximum benefit from your Mastery: Chaotic Energies.
Scalding Flames has been redesigned — Increases the damage of Immolate by 25% and its duration by 3 seconds.
Chaos Bolt is now learned at level 10 (was a talent).
The cooldown of Summon Infernal is now 2 minutes (was 3 minutes).
Raging Demonfire now extends Immolate by 0.5 seconds (was 0.2 seconds).
Chaos Bolts cast by Summon Overfiend no longer gains modifiers active on its summoner.
The tooltip of Summon Overfiend has been updated — Generates 1 Soul Shard Fragment every 0.5 seconds and casts Chaos Bolt at 80% effectiveness at its summoner’s target.
The visual for casting Dimensional Rift has been updated.
The following talents are now 1 point: