What is more pure World of Warcraft than the dark hearted Warlocks? Casting destructive spells, controlling demons and inflicting excruciating amounts of pain. It's one of the most fun classes to play (and my personal main so I may be biased). Warlocks are the flip side of the Paladins, living in the shadows and avoiding the light. But embracing the darkness does not make one evil and the powerful casters can be just as heroic as any hero that follow the light. (Told you I was biased.)
As with all classes, the Warlock breaks into three specs each with their own specialization. An Affliction Warlock casts curses and spells that cause damage over time, with each tick of the DOT causing greater damage. Destruction Warlocks hellfire and flames to devastate their enemy through a barrage of attacks. And Demonology summons foul creatures to battle for them… well, that was the basic idea but somewhere along the way they got sidetracked and began to transform into demons themselves. That part is what Blizzard has decided to focus on along with the resources Warlocks use. Their plan is to make Warlocks function using mana and Soul Shards again and to make each summoned demon stand out from the others with advantages to using them.
Starting with Demonology, the focus here is returning to summoning demons rather than transforming into one. New will be the ability to summon 2 Dreadstalkers to attack your opponent for 12 seconds… this ability will cost 2 soul shards and have a 15 second cooldown. Also the Hand of Gul'dan will summon anywhere from 1 to 5 Wild Imps depending on the number of soul shards to attack your opponent as well. You can channel Demonwrath where all enemies around your demon take shadow damage and your Mastery talent increases the damage your demons do. And if you do summon the Wild Imps, you can then use Implosion which will yank all of your imps to your target then having them explode damaging your target and nearby enemies. That sounds like fun.
With Affliction, they want to re-emphasize the damage over time spells, making them the main source of your attack rather than just enhancing your single target spells. So instead of constantly throwing Malefic Grasp with a few curses mixed in, you'll be more focused on best using your DOTs and with the occasional Drain Life when you're bored and everything is ticking away. And that is another thing, your filler spell will be Drain Life rather than Drain Soul or Malefic Grasp to make it keep with the Affliction lore better. Also, you'll build soul shards from Agony you have on a target, making the more Agony you spread the better. Affliction Warlocks, the ex-spouse of Warcraft spreading agony and damage over time.
And finally we get to the Destruction Warlocks. This is a spec that Blizzard felt was already in a good place, so they are just polishing it up. Burning Embers are changing back to Soul Shards to keep with the overall Warlock theme. Your rotation will remain basically the same with Incinerate, Immolate, Conflagrate and Chaos Bolt being the big four and your Mastery focused on increasing your damage per second. But a nice new spell will be Channel Demonfire which launches 15 bolts of felfire at Immolated enemies within 40 yards. It last 3 seconds causing moderate damage and is of course a channeled spell. There is a 12 second cool down. I can't wait to see this one… if it will be 15 total bolts or 15 per nearby immolated enemy which would probably look like a downpour of hellfire. That thought makes me happy.
So Warlocks are coming out of this with a few mechanical tweaks, a couple new spells and a re-emphasis on what makes them unique. Tuning up the actual demons sounds like a good idea to me as right now Warlock tend to one with one kind of demon only… and since you get five or six that seems like a waste.
For more on the proposed changes to Warlocks, check out this write up from Blizzard.