If you look at most classes, there’s usually 1 or 2 – with fighters you have an auspicious 3 but it boils down (generally) to two – tanking or more DPSing, meaning fundamentally a blend of tanking and vanguard or 2 handed. With barbarian you talk mainly about forms of DPS – do you prefer more one subset with temp HP or do you like a similar type DPS but with other features?
Wiz have two – archmage or Pale Master – sure, there might be some that try the Eldritch Knight (as you can with Sorc) but it’s doubtful it’s that widespread. Similar with FvS and Cleric – most will look at either a spell centrist caster or a ‘healer’. Fewer will most like go for the melee type – altho it’s there (I suspect in that case you find more mix of Pally Clerics or Favored Souls than pure with the melee tree).
Bard got 2 – melee (Warchanter or Swashbuckler) or Spellsinger. Druid similarly caster type or melee type. You go down the line and you find the same with Pally’s, Rangers and Artificers. The one exception to this might be rogue that with some well guided hair splitting can be split into assassination (insta killing), Acrobat or Mechanic – ultimately however we’re not talking about a massive difference of form of death – mostly methodology.
Setting aside whether you use ranged, close out or a dagger under a rib into your hearth you can roughly state that most classes method of DPS range from CC, melee, ranged or spell casting with a plethora of methods of those without different classes. To that end Warlocks are not really all that different, only a little bit more limited in spread.
I’ve mentioned that ideally the pact decide much of the flavor in what you’ll specialize in. That’s unlike most (if not all) other classes where utility is a lot more interchangeable. A ranger for example can easily retool to arcane ranger from DPS, given good enough weapons – and very few changes in feats.
Sorcs can easily switch between elements since most feats work just fine with all elements (almost) and it boils down to available gear.
Similarly with wiz – true – Drow is better for Pale Master and most people running Archmage use robots, but it’s not a must.
And since Warlocks pacts adds specific flavor, it’s always better to pick the pact (and featured pact specific items) and blend the trees that fits that pact. Doing it the other way around like you would on say a Sorc (pick sorc and start putting points into the trees), it takes a little bit more initial planning in order to maximize potential.
The current three Warlock options are Soulteater (SE), Tainted Scholar (TS) and Enlightened Spirit (ES). Both SE and ES offers melee options, Tainted Scholar is great for sustained Edritch blasting and Souleater in particular offer many insta killing options.
So in order to maximize pact and tree, look at the pacts first. Fey offers CC (Otto’s), Fiend single CC and a nice insta kill spell and Great Old One, several charm options.
So if you’re looking at CC options I’d go Sustained DPS through Fey, TS and ES, if you’re looking at insta killing I would go Fiend and primarily SE and Great Old One is perfect with a melee oriented ES heavy hybrid or pure build (for melee it’s better to multi class).
So lets talk sustained DPS. To me sustained DPS is a raw output of average high dependable DPS with few high spikes. The theory is that you know the given DPS without relying on particular spikes of burst DPS. Since Warlock have very few big sticks, you’re talking Eldritch Blast. Most of the bonus to that is found in Tainted Scholar which blends higher pact damage, for variants of blast focus and type and also adds a good mix for your CC type activities. You have the ranged AOE for dancing creatures, you have confusion to make mobs turn on themselves and you have blast types that turn the force damage into untyped or evil, or even can slow down creatures or neg level them.
TS is perfectly served with ES. Here you’re looking for the burst and if you want to go tier 5, also a good source of temp HP. And if you want to make it sustained DPS but with a few dots, you can always mix in SE instead. But here I still recommend tier 5 TS – that’s for DC breaking and AOE damage. This combination with be strong against trash mobs but a little weaker against bosses.
With SE you get lots of insta killing options. Add fiend to the mix and you have the fiend Hurl through Hell, the cap stone which adds a soul ripper effect, tier 5 offers a Finger of death SLA and you can always pick the spells wail of the Banshee and Finger of death – adding a lot of sources of insta killing. Many low cost version of killing and 2 spell based ones.
SE also adds 2 powerful evil damage based dots – consume and stricken, both with multiple ways of increasing the potency and other features like one that can do stat damage and transfer ability points (temp) to your Warlock and one that outright steals HP from the opponent and gives it to your guy.
SE can also be combined with any of the other trees but work well with TS due to either can boost DC and the blast combined with dots makes for a good spell casting type Warlock.
However if you’re looking for a solid melee Warlock than ES offers the best options. 2 possible bursts, one damage ticking aura and several ways to boost aura damage (including weapon damage) as well as PRR, MRR and even hirelings.
Add to that a very string tier 5 temp HP source (12x your CON, used to be 15 but that’s changing in U27) every 30 seconds. You don’t need to combine this one with anything else; you’re most likely going to multi class anyways so you get all the melee boosting features on it’s own. The burst will be instead of melee cleaves (shares their cooldown) and the aura is passive and does damage up to 2 seconds per tick dependent on how many core abilities you have.
I’m currently running 3 Warlocks – one operates as a multiclass Vanguard/Warlock. I think most of the issues I got there is the gear choice. It’s not bad, just not as strong as I want it. And to be perfectly honest – Vanguard is probably not the optional melee choice. It’s feat and gear intense and you end up compromise too much.
I also run a dotting, slight insta killing Fey based casting Warlock. So it’s not primarily anti killing – most of the damage is from dots and blasts but no bursts.
My other Warlock is Old One acid based and blends heavy ES with a solid up to tier 4 TS. The idea is mixing blasts and heavy burst together with survivability through temp HP. Old One offer 2 insta killing spells – phantasmal Killer and Power Word: Kill but it’s not primary features like with my Fey based SE Warlock.
So, if you want to avoid reading all this – just Pact and plan how you will deliver damage. Pact is very dependent on your preferred alignment but it will also set the tone in strengths vs weaknesses.
And finally have fun; Warlocks are fairly maintenance free and will keep on ticking well beyond when classes like Sorcs start running out of juice. But you won’t be king of DPS, just solid in almost all aspects.