In case you aren't already reading it, I'm still writing a weekly column on Tribality.com exploring the history of D&D's classes. Once I got to the end of the Druid, I took a vote on what I'd write next. It looked like the Paladin would score an easy win, but after I had started writing, the Warlock cut some kind of dark bargain and surged from behind. But, well, there were already words on the page, so I'm writing about Paladins first, then Warlocks. Anyway, the point is that I perceive some key problems in the design of the Warlock class, and I want to talk about them.
Now, I recognize that WotC's designers are some sharp people, and I believe there might be gaming contexts where more of their decisions on the warlock work out well. In the patterns of the games I run, it's rare that players take more than one short rest in a day, and three or four would be quite a surprise. Most combats take, at a rough estimate, six to ten rounds, with occasional much longer combats. A single session with more than three combats, unless it's an all-day session, would be quite rare. Large parts of most sessions are social encounters or investigation scenes. In that context, then, Kainenchen is playing a fey-pact warlock, dedicated to Verenestra, and currently 4th level.
Eldritch Blast and the Agonizing Blast Invocation
It isn't that the class doesn't work; it's that they often trade interesting options for effective options, and that's sometimes too effective - so good that it's not much of a choice, really. Eldritch blast is like this, and even more so once you receive your first invocation and (probably) pick up Agonizing Blast. Eldritch blast has a d10 damage die and the Force damage type going for it, which makes it the best damage-dealing cantrip in the Player's Handbook, and the only one restricted to warlocks. Fire bolt is almost as good, but there are a lot more immunities or resistances to fire than there are to force - in fact, are there any force immunities or resistances? The new spells of the Elemental Evil Player's Companion only exacerbate this issue. The fact that at higher-level eldritch blast fires multiple separate blasts rather than a single bolt is a wash in terms of power - it normalizes damage toward an average, because you're unlikely to hit or miss with all of them the way you might with a single bigger cantrip effect. It's a huge deal when it comes to Agonizing Blast.
Unsurprisingly, eldritch blast has a lot of fans in the character-optimization crowd once you add in Agonizing Blast from a second level of Warlock: "When you cast Eldritch Blast, add your Charisma modifier to the damage it deals on a hit." We can effectively treat that number as +5 for all single-classed warlocks, and probably +3 or so for others. One of the most common questions from this is, "Does this apply to every separate blast?" To which Jeremy Crawford says:
Does Agonizing Blast add damage per Eldritch Blast casting, or per beam? E.g. 5th level lock deals 2d10+2*Cha, or 2d10+Cha? I would rule that you add your Charisma modifier whenever a beam hits. But I have my eye on this feature. -J
Compared to classes that can't add a stat bonus to their cantrips, and compared to cantrips to which warlocks can't add their Charisma bonus, this is doubling the average damage - inasmuch as +5 is very close to the average of a second d10 (5.5) for every beam of the eldritch blast. Other classes gain an ability score bonus to damage for some of their cantrips (Draconic Sorcerer, Knowledge Cleric, Light Cleric, Evoker Wizard), but no one gets four times their ability score bonus to damage for cantrips.
The truth is, though, without some kind of damage bonus to cantrips, a lot of them are pretty underwhelming. A brief perusal of forums suggests that many people come to the wizard expecting pretty steady damage output, but from 1st to 4th level, there's a real chance of even your fire bolt doing less damage than you would with a light crossbow and a modest Dexterity. The warlock has hex, and hex is really cool (I appreciate both the ways it is and is not 4e's Warlock's Curse), but if the game expects you to toss one of those out in every fight and you go a "standard" two combats per short rest, you're never casting anything but that, and that's pretty dull.
Agonizing Blast seems to solve this problem, but there are two serious problems with it as a solution.
It makes one cantrip hugely better than all of the warlock's other options. When one choice is obviously much better than all other options, the character's combat round isn't an interesting decision. It's good for the warlock's effectiveness, but bad for the overall interest of their gameplay.
I talked before about a similar problem for weapon-wielding characters. This is the same, except that there's less variation in the weapon type from warlock to warlock. (Blade Pact warlocks are excused from this comment.)
If every build of warlock is well-advised to pick up the same invocation, even melee builds, that's a sign that it's much too good. It's more like an invocation tax than a build choice at that point. If WotC (correctly) anticipates that every warlock is going to have this invocation, it needs to be a class feature instead of a false choice.
There's actually a third thing that gets into what happens when you have Agonizing Blast and Crossbow Expert: you have a one-handed weapon that deals 1d10+5 force damage out to quite a long range, and scales up to four times per round.
I have a solution that will, I'm sure, be controversial among those who care about such things. I think Agonizing Blast needs to go away entirely, along with Lifedrinker and Thirsting Blade. Spending invocations on passive abilities that maintain your damage output on your baseline at-will abilities has to be the least interesting but most necessary of options. Fold Lifedrinker and Thirsting Blade into the core of the Pact of the Blade.
But Agonizing Blast stays gone, and instead every cantrip increases its damage value by +2. For eldritch blast, this bonus applies only to the first beam that deals damage in a round. This is pretty much entirely to help spellcasters of levels 1-4 feel like they're contributing to the team. Granting the full ability score bonus is too good - it's the equivalent of a weapon attack, and the character also has per-long-rest or per-short-rest powers lying around to really bring the pain. On the other hand, low-level spellcasters don't have enough slots to balance the scales there, especially not if there are any utility spells needed of them.
Why all of this focus on low-level spellcasting, though? Probably a lot of it does even out at higher levels. There are a few connected reasons: first of all, low-level play is where you set the hook for new players. 5e's low-level game loop is good, but if someone's relatively experienced with games but not sure about this game, having a frustrating or underwhelming experience as one of the many spellcasting classes is not so good. Secondly, my campaign advances glacially slowly, in part because of the shifting player roster and in part because I don't hand out a lot of XP. Kainenchen's warlock is 4th level, and finds everything in the game enjoyable except combat. If the answer is, "Buy Agonizing Blast and then you'll have fun," then that's a design problem.
Alternately, I'd look at something to give the warlock more to do with their bonus action (other than casting or reassigning hex) that had the effect of increasing their damage. Classes like the Monk and Rogue get a lot of tactical interest out of their bonus action options, and I think giving the warlock could stand to get in on that.
For my group, Pact Magic is so close to being really fun. Spell slots that come back after a short rest, and they're always equal to your highest-level* spells (*: or 5th level, whichever is lower)? What's not to like? Well... it turns out that casting a non-cantrip spell just twice between short rests (because 11th level is a long way off) is not getting to be big and bad all that often. It's a common refrain for me, but I'll sing it again: what I care about is interesting choices, and while scarcity gives decisions heft, it also means you might go a long while without seeing a compelling choice. Oddly, when the scarcity goes away, it goes away from two different angles: warlocks get their third Pact Magic slot at the same level they get their one sixth-level spell for the day.
In addition to their spell slots, warlocks may also receive per-short-rest powers from their Patrons, some of which are useful damaging or crowd-control powers like Fey Presence. Over the course of the whole progression, everyone gets at least one new per-short-rest power. Really, the only problem with Fey Presence is that it costs an action for one round of crowd control, on a failed save, and a huge number of monsters are immune.
I've already mentioned the issue with hex - you may be able to keep it moving from target to target for the whole battle, and it does feel cool to make that work. On the other hand, it's really not interesting if your whole combat routine is hex and eldritch blast, lather-rinse-repeat; that falls far short of the standard of interest established in 4e's warlock, and that makes me sad.
I think there are simply not enough Pact Magic spell slots, especially considering that several invocations allow you to cast an extra spell... at the cost of a Pact Magic slot, which looks a lot like paying twice for a single power. More specifically, I think they should get a third spell slot at 5th level, making the slot they receive at 11th level their fourth slot, and the slot they receive at 17th level their fifth.
I don't know that all of those spell slots should be at the highest* spell level they can cast. Changing it so that one of their slots (once they have at least two) is always one level down might or might not add any computational burden on the player, but might also help with the balance issues.
Wait. This is ridiculous. I should just extend Mystic Arcanum downward. Getting a once-per-day casting of a 1st, 2nd, 3rd, 4th, and 5th level spell at 1st, 3rd, 5th, 7th, and 9th levels would be cool, and would give the warlock a panic-button currency to think about. Okay, I like that solution pretty well.
I'm interested to hear other people's experiences with the 5e warlock, especially if you also played a 4e warlock for any length of time. For me, the 5e warlock is a really interesting class with variety and great story opportunities that just falls a little short on tactical variety, and my players and I care about that a lot.
For that matter, I'm also interested in how closely other groups keep to the schedule of one short rest per two combats or thereabouts, and how many combats you're likely to see in a day.