I'd like to make a case for demonology warlock. While it's nowhere near outlaw rogue, hear me out: Demonbolt is your highest dps and very nearly all we can do that's not summon a demon. However it's cast tone is nearly 5 seconds, but the time it's cast you could have done so much more that it's not worth it. So it's a dead spell...unless you have a charge of Demonic Core, then Demonbolt is instant.
How do we get Demonic Core? Imps - wild ones. They last about 8 seconds then expire or you can throw them at the enemy using Implosion. Each imp that is consumed or expires has a 10% chance to give you a demonic core charge. Still with me?
You DON'T get a chance at demonic core if the imp is killed. So if a boss drops an AoE spell or kills your imps, you get nothing. I hear you, that sounds like it could still be consistent. No. It's not. See you have a cap on demonic core stacks. It's 4. So what happens if you have 4 already and you have to move due to mechanics? Those imps that would have given you charges to to waste. This compounded by the fact that you can't just throw Demonbolt when it's ready. You see Demonbolt ALSO generates 2 soul shards. You use these shards on various other spells that have cast times. You can't do that when you move, so your dps is brutalized if you have to take a step away from fire or what have you but if you're capped on core stacks, you can't spend shards. Can't spend shards so you don't cast Demonbolt, you don't want to waste them. Will you get a charge on the next 5 seconds? 30 seconds? Who the hell knows?
This all sounds manageable on paper but here's the real kicker: remember what I said about it the imps die to attacks? You can't control them. You can't pull them off anything, you can't make them move. So...well they follow you if you move? Stay put and die for no charges? Expire and give you no charges? Expire and you get free Demonbolts? Nobody fucking knows.
Demonology warlocks aren't bad DPS like everyone is saying, it's that if we have to move we are punished because we stop making imps or RNG just hasn't given us anything in over a minute so we're stuck throwing out shadowbolts and hand off Gul'dan just waiting for that big payday of core stacks so we can go ham on the boss for about 8 seconds.