Warlock is eye candy class with really bad mechanics and design. Warlock gameplay are infested with bugs, bad gameplay design choses and tech. limitations.
All warlock specks works the same way
Gain max shards.
Summon infernal(Destro), Stack imps(demo), Stack UA on the target(affli)
Stack buff from grimoire of supremacy(destro), Summon tyrant(demo), summon darckglare(affli).
Deal massive damage.
Wait 3 min for repeat(Destro/Affli), wait 1.5 min to repeat(demo).
Demo is particulary broken, because demons AI is worst AI in the game, hunters and DK at least have tools to efficiently control their pets, while we cannot do the same.
All talk that warlocks are “gods” in PvP are comming from people who never fought an actual good pvp player, or people who didn’t bothered to closely study the current state of the warlock.
Yes the rough damage numbers can be good, but numbers are nothing when your overal class design is just a mess, that no one in blizz are intend to fix.
Warlocks was good in the past, but now, we are heavily pruned class, that only have rough damage numbers and nothing more.
This is a good old topic that summarise warlock and demonology problems.