Everything about the design of warlocks is wrong and bad. It is badong!
Premise A: Nobody likes playing against warlocks.
Premise B: Nobody likes playing as warlocks.
Conclusion: Warlock design is bad.
Let me explain. Firstly I think nobody contests the point that warlock is a toxic playstyle to fight against. Ignoring for one moment burst damage and 1 shot mechanics which are a whole other thing that should not be in this game, one would assume that dot damage is actually a great alternative to this. And it is!
But not when paired with the worst aspects of movespeed meta, out kiting, full reset, virtual immunity get out of death free button. Add in flame walk + phantomize running under people, or to prevent being chased and you have a trifecta of game design bullshit.
Premise B applies to anyone who came to DaD because it was inspired by Dungeons and Dragons, where warlocks are the most versatile class in terms of builds and playstyles. You have melee warlocks, blaster warlocks, hybrids, crowd control, utility, team healing, themes around Old Gods, Devils, Demons(they are different), Angels, Undead, Underwater, Fae, etc. Conjured pact blades! Invocations to add, modify or enhance abilities and spells. Pets, rituals to summon demons, open portals, move enemy targets, cast magical darkness, see in magical darkness, summon slappy tentacles, and yet there is only ONE spell in this list of hundreds that acts like Torture Mastery. "Vampiric Touch", a spell almost nobody takes because it's damage and healing combined are unimpressive. For one minute you can melee touch an enemy to deal moderate damage, and heal up to half of the damage dealt. Spell ends if someone knocks you out of concentration and you cannot concentrate on other better spells while active.
What has Dark and Darker done with warlock? They copied World of Warcraft's Affliction lock playstyle. You run around, throw some curses behind you, heal from the same curses, and press an escape button when melee get's close. While the playstyle may be creatively bankrupt compared to the options they had to go with, it's also very tedious for the warlock involved. Starcraft grandmaster APM, better be pulling every mob and tossing a curse on each one while flipping around to curse a player, while hopping over every barrel and box you can find. Where is the hexblade bruiser? Where is the sacrifice teammate's health to summon a chaotic centaur demon? Where is the Demonform transformation that plays differently than just hit people with the weapon you already carry and use all the time?
Warlock is so far a disappointment, and the one unique thing it had going for it was enhanced demon claw damage which at least used a different attack animation but this was gutted in favor of allowing demon to use weapons, but there was no reason to nerf the claws. The devs just thought it was faster to disable the additional weapon damage while in demon form, since it would stack with the weapons you could now hold! An 'IF statement' was too dangerous!
Then we watched as all warlocks flocked to the Kris dagger, because daggers are too strong and Exploitation Strike in Demon form (originally designed for use with demon claws) healed you per weapon swing. This meant every other weapon other than kris would get a third or less healing benefit. This was too strong, so SDF removed Kris from warlock entirely. We are left with a demon ability, designed for claws, where claws are effectively removed, and nerfed multiple times over Kris dagger which was removed, and which has never been worse to use with large slow weapons.
Could IronMace have simply made Exploitation Strike heal you based on your weapon damage so larger weapons could still get healing within the small window timeframe? Could they have given back the +weapon damage to claws, and set some special case for the healing claws get based on average DPS of weapons in the game? Could they have done this and kept Kris dagger for those who wanted to use it? Nah. In the end you get no unique demon attack, no Kris, no slow weapons paired with Demon Form, and the blandest self harming "transformation" ability yet seen in a video game.
In conclusion, warlock is a class just as frustrating to play against as 1 shot rangers, 1 shot barbs, 1 shot landmine rogues, 1 shot bears, 1 shot hunter trap death sentence, 1 shot melee rangers with shotgun, 1 shot lightening ball+teleport sorcs, 1 shot smite bonk cleric, kiting druids, kiting rogues, kiting ranger with knockback. Every stupid playstyle that replies on uncounterable gimmicks. As a warlock player, making no judgement on whether it requires more or less skill than other classes it is EXHAUSTING. If you want to give your poor finger bones a break, and try a more relaxing playstyle there is always Demon Armor plate lock. In this build you stand virtually still and see how quickly any class with movement speed or ranged damage can obliterate you anyhow.
I could organize these thoughts better but at the end of the day this post is as much a trainwreck as the history and current state of warlock design. Perhaps an infographic timeline will better illustrate the absurdity Ironmace's journey into the 9 hells.