Sword of Spirit
Legend
[MENTION=6677017]Sword of Spirit[/MENTION] - That certainly looks like a detailed graph. I will take a look a bit later. But I agree that the Warlock could play more like a spellcaster with the right build. But if the Warlock is supposed to be a true spellcaster in the vein of the sorcerer or warlock, you shouldn't need to build it to make it feel or function like that. Which once again, at least to me, supports the idea that a Warlock shouldn't be a spellcaster. The mechanics don't really support a strong enough identity for players to know how to build a functional warlock build without a good deal of system mastery. To me, that seems like a problem, since a player using a sorcerer or a wizard does not need advanced system mastery to play those classes as they are intended to play by the designers. So, the choice seems to either lean into the spellcasting aspect, or disregard it. I am more in favor of the later.
It sounds like you want to revert to a more 3e warlock, which I enjoyed, so I'm sure that would be fun. I also really like the 5e spellcaster warlock.
I completely agree that system mastery shouldn't be needed to get a class or subclass to play like it looks like it should. That's my criticism of the Blade Pact--it takes a lot of system mastery, and a ridiculous amount of build space to make a character that doesn't do any more damage than one that can be made with just one cantrip and one invocation (and suffers in other areas).
That said, I'm not sure I agree that it takes system mastery to make a full caster warlock. In fact, the choices that I took to build it are actually what I would consider the most obvious choices. Pact of the Tome, and Book of Ancient Secrets. Take invocations that grant at-will spells, and you're done. You now actually have more daily spellcasting resources (both high and low level (through at-will spells)) than a wizard (assuming 2 short rests a day--and playing in games that don't provide that is I think part of the issue). You do have less flexibility in chosen spells (though you'll know more than a sorcerer will), but in exchange you have better HD, armor, weapons, and the most powerful at-will spellcasting attack in the game.
I think where the disconnect comes in is that people want to invest their resources in non-castery things, like Blade Pact, or Chain Pact, and additional invocations that boost eldritch blast, instead of the spellcasting, and then expect to have spellcasting on par with a wizard or sorcerer. What warlock does is provide options to weaken your spellcasting in exchange for other things.
That said, there are enough people who think the class doesn't play like it seems to be presented that I think there must be something to it (although probably not quite as much as is often stated, due to the issue with short rest availability). I wonder how people would feel about the class's functionality if they just multiplied the warlock's spell slots by 3 and made them recover with a long rest.