I personally find the "best" warlocks, as in the ones most fun to play are the ones that are not designed to min max damage. Why? because The warlock at first level has huge 1st level damage potential with 1d10+1d6 damage per attack. Take eldritch blast as one of your cantrips and take hex as one of your 1st level spells and you use just these two spells for ALL of your damage output for the 1st few levels. And you will be at the top or near the top of the party in damage. So when you try to max out your damage you sacrifice your versatility for little actual gain. This seems to have been true for all editions of the warlock as well.
The versatility of a warlock is found in their invocations vs their spells. I ran into a Warlock that was a member of a Druid circle in a campaign. Fey pack warlock that was their master animal liaison. The warlock has the ability to be superior at speaking with animals than a druid. They can speak with animals at will. And with the warlocks superior charisma they could persuade animals without the use of spells far easier than a druid. Is a druid more versatile in the wilderness? By far but a specialized warlock could obviously be of use to a druid circle, Imagine them like a lay person in a church not a priest but still a valued member of the religion.
I played a master assassin Warlock, I could get into near any location, use darkness to isolate my victims blinding them and with a few choice invocations was able to completely change the "feel" of the warlock from caster to infiltration assassin expert.
We will have to see if the game gives warlocks the ability to use many of their invocations in creative ways. The wizard's power and diversity all comes from their spells, a warlock's power and diversity comes from their spells, invocations and pack boons. So if you focus on only a singular aspect of the class it will always look weak, but warlocks have multiple different features that other classes don't have. and the whole has to be used to judge the class.
Which begs the question, which Invocations actually work. Neither of the ones I took do currently. Does the speak with animals invocation work, because that would be incredibly useful in this game right now.
