Why, you ask?
Well, let's forget all about numbers and theorycrafting, and concentrate on stuff that doesn't change every patch. Tell me: What can your class do?
Can you blast them with the cold dark of the void? So can we.
Can you burn your foes to death? We can too.
Can you frostbite them with sub-zero temperatures? We can do that too.
Can you sicken them with the substances of nature? We can do that too!
Can you charge them with arcane energy? So can we!
Can you masterfully destroy them with physical blows? We can too!
Can you smite them with holy power? Believe it or not, WE CAN DO THAT TOO!
And all at the same time. with our instant cast SPAM spell, Touch of Chaos. ToC does Chaos Damage. That means it deals shadow, fire, frost, nature, arcane, holy and physical damage at the same time.
You, non-demolock, do you have a Chaos spell? no? I thought so. There are only TWO Chaos spells for players in-game and they both belong to demolocks. The other one is Chaos Wave, if you wish to know.
Warlocks are the "Evil Mega Man" class. We take our powers from our enemies:
Burning Legion? We got most of our spells and all our Minions from them.
The Illidari? Oh, we copied your trademarked transformation, Illy. Hope you don't mind.
The Scourge? Can I has your soul weaving necromancy to use Soul Shards, Death Coil, Soulshatter and Haunt my enemies? Well, you don't have a saying on it, anyway
Ragnaros' Elementals? we went there and made our flame spells much better. Burning Embers came from there
The Old Gods and their Twilight Cult? Malefic Grasp is within my grasp. Twilight Ward is within my ward (?)
And Garrosh... well, I don't think there's anything of worth to steal from Garrosh, but we'll figure something out
Anyway, as I said, we are the "Evil Mega Man" class. And within this class, Demonology is the most class-defining spec!
Any class can destroy stuff, like Destruction. if you think about using fire, Mages and Shamans can do that too.
Shadow Priests and Death Knights can also afflict people with many slowly devouring harms. And even shamans can curse (Hex).
But Demonology, that one is about demons. How many classes out there, besides warlocks, use demons? How many summon demons? How many turn into demons?
The Answers are: 0; 0; 0.
Demonology is unique. It's Cool. You have 2 forms, like an evil Saiyan, or a video game Last Boss, and you use your lesser form to power your greater form up, and than beat your enemies to a pulp. You can even tell people "this isn't even my Final Form".
And you do that with Chaos. You do that with EVERYTHING TOGETHER! Arcane, Fire, Frost, Nature, Shadow, Holy, Physical Damage, Everything! Not even the ORIGINAL MEGA MAN can use all powers combined into one attack like that. We've surpassed everybody, including the Blue Bomber!
Plus, we can do some limited Tanking (Dark Apotheosis) and Healing (healthstones, self heals, Symbiosis), besides doing everything else.
DEMO LOCK PRIDE!