:re Warlocks and Warlock issues as a lock main since Wrath who does Heroic raids but not Mythic
Warlocks have always been weird but now we're in an even weirder situation with Demon Hunters stealing one of our specs. The idea of being a tanky caster that can absorb and self heal was cool, but since we lost Metamorphosis we also lost the possibility of Demo becoming a Tank spec which would have been cool and unique. I also don't know why things like Burning Rush and Demonic Portal (our only movement options besides Gateway) aren't baseline. Doesn't help that Demonic Pact is no longer baseline either, so our only defensive CD is Demonic Resolve. Oh and we have no real interrupt unless you want to use Felhunter or Grimoire: Felhunter (you don't.)
I think the real issue is that the current Warlock specs are good/decent in one area and one area only and you have to completely spec into that. You can't have good single target, multi-target and AoE damage all in one. You have to put all your chips into one spot.
Aff - Oh boy. Affliction. First off - Affliction's artifact ability and 2/3 gold traits rely on a feature that Ulthalesh no longer has. Ulthalesh used to spawn souls on its own for you to kill and reap which would trigger gold traits and artifact abilities but that doesn't happen anymore. On a fight with little to no adds? Fuck off then because your uptime on Reap Souls will be downright pathetic. And you wouldn't use Affliction in a raid anyway because the single target damage is shit even with Soul Effigy, Write in Agony and Siphon Life.
Where Aff does have an advantage is AoE if you spec into Sow the Seeds and Phantom Singularity (PS I like but it tends to pull stuff so it can be hard to use in some dungeons.) Now Aff's version of AoE really only takes effect when the tank can pull a big group. 3-4 anyone can do AoE on, but double or triple that Aff starts to downright shit damage. Sow the Seeds and then make it pop once and you are in business, even without Absolute Corruption. Continue sowing the seeds and using PS as needed and once mobs start to die, Soul Flame will trigger and can cause a chain reaction where everyone just explodes if they are all around 10-15% HP. In Nightbane runs, I usually outdps everything but Death Knights as Aff and its my preferred choice for Mythic +. I also have Unstable Horrorslime and Aran's Relaxing Ruby which help with the AoE too. Because of this its also my preferred leveling/WQ spec.
Another issue - Aff is a fucking snoozefest to play. Here are your base abilities - Corruption, Agony, Unstable Affliction, Drain Life/Soul. That's it. Seed of Corruption is useless without Sow the Seeds so I'm not even gonna count that, and your main shard dump is UA while your buffer ability is...Drain Life/Soul. Even when you throw in Soul Effigy and Siphon Life its still a snooze to play unless you are doing Dragons, which you wouldn't use Aff on since Destro dominates that fight DPS wise.
Demo - Hey remember when Blizzard said they didn't want to have a spec where add-ons were essentially required to play? OOPS THEY MADE ONE.
Demo is weird. The revamp certainly sounds cool on paper - become the master of a neverending swarm of demons and overwhelm your opponent through ankle biting. In practice, demons are fancy DoTs. DoTs that you have to cast a spell (Demonic Empowerment) to make them do anything. Every. Single. Time. Unless one of your demons is going to come off cooldown in a second, you will cast DE every single time you use Dreadstalkers, Hand of Gul'Dan, Summon Darkglare, Summon Infernal/Doomguard or a Grimoire. DE isn't instant cast either, so if you have to move at all during the fight then your DPS will tank. The demons also don't last long at all, so your rotation is an extreme clusterfuck, and you gotta make sure to keep Doom up 100% at all times on every solid target.
But the real add-on kicker is Skull of the Man'ari's artifact ability, Thal'kiel's Consumption. It takes 8% of each demons health and then deals it to your target. This can get to some real high numbers but it requires you to keep track of how many demons you have, make sure they are all buffed by DE, and won't expire before you finish casting. And its on a 40s cooldown. And you need to line it up with the rest of your cooldowns. Its...complicated.
You get shittalking floating skull though so it's alright
Destro - I haven't put a lot of time into destro at all but Havoc owns on Dragons and the mastery is just RNG.
You can get Rain of Chaos tho and that owns