TLDR: Lore is an equally important reason for picking a race other than animations and appearances. The player character should have no restrictions but some races should not have this option represented in the lore whatsoever or only very little, maybe with 1-2 NPCs. There is a lot of critical analysis in this post, so if you are incapable of critical thinking or incapable of discussing the sociology of a fantasy culture, then you should ignore this post.
Listen, I get it. There are certain races people like to play because of racials and animations and so on. We all have a preferred arrangement of pixels. I can get behind wanting to play your favorite class on your favorite race.
However, for how many people pick a race because of mechanical things, there is an equal amount who pick it for lore and flavor.
Ultimately, cultures are just a collection of individuals. However, just because that is technically true, it is also true that cultures are made up of individuals who have similar beliefs and mindsets; otherwise, we would not define nor group things as such. If you look at America, we have many different subcultures, and we do have some with radical beliefs, ultimately, Americans have cultural norms that the majority of us share and agree on. Not necessarily because they are right, but it just so happens we share them.
The same can be said for fantasy universes. Our player character in WoW is an “extreme individual.” We have stopped world-ending threats, slain near Demi-Gods, participated in great wars and have been to many different worlds and even the known afterlife. The same cannot be said for the majority of our factions. While each races has powerful facets, ultimately, they do not have the agency we do; the majority of these individuals share the same beliefs and live very similar lives, and this in turn creates the flavor and lore of the races we play as.
Groups that have not fit in have existed for a very long time; Orcs, despite their heritage, were only allowed tenuously in Thrall’s Horde. Even then, all the way back in vanilla, individuals like Neeru Fireblade existed. However, let it be known, that many orcs willingly drank the felblood because it seemingly aligned with their desire for conquest, despite the fact they did not understand the long-term repercussions of it, or, if they did, they did not care.
I am all for allowing the individual player to have access to all classes. Like I said, we are extreme individuals with extreme agency. However, culture wise, the same cannot be said.
The Draenei and their culture are the best examples of this. You can have headcanon all you like, but whether you like it or not, your draenei was on the Exodar. Even if they somehow were not on the Exodar, they are apart of a race that fled for a millennia from the Burning Legion and were genocided by the Orcs. You can make all the excuses you want, but there has never been an NPC-aligned Draenei warlock; they are either all man’ari or working the legion, as saw in Legion. The man’ari could potentially be accepted back, yes, but it have to be done by Velen, considering not all draenei are tolerant. This is evident by quests in Bloodmyst Isle.
The same can be said for lightforged draenei, even more so, considering that they are light-infused weapons of the naaru. They were on Argus the entire time, even after the draenei fled, and they fought the entire time, and not once do we ever see a lightforged warlock; the opposite is true in fact, we see light-infused demons. The lightforged would most likely exile or execute any lightforged that defected and began to use fel magic.
In my opinion, there should be no friendly draenei warlock NPCS.
The mag’har are united due to their rejection of the demon blood. However, they are more justifiable than the draenei. Kilrogg drank the felblood afterall. I can see a player character mag’har more easily, and maybe a few NPC rejects after they lost Draenor, but, nonetheless, the majority of Mag’har will not take kindly to this betrayal.
Normally, I would say night elves should not be able to become warlocks; given their history with the Well of Eternity and the Legion. However, at this current time in the lore, if there was a time for them to become warlocks, the time is now. Think about it, the loss of Teldrassil was a deathblow to night elven culture as we know it. Ever since the Well, and the loss of their immortality, this is the lowest the night elves have ever been. Besides, a small group of night elves (who lorewise are insane, read the Illidan books) followed Illidan and become Demon Hunters, who I would argue are Warlocks turned up to 11. With the seemingly overwhelming nihilism I imagine most night elves find themselves in, I could see them succumbing to dark magics.
The Tauren… technically speaking, I believe our tribe is ambiguous, and that we are just allied with Thunder Bluff, but all throughout the starting zones and quests, I would say we are not playable Grimtotem. Even then, not all Tauren are good. The Grimtotem were the longest standing examples of that, but also the Bloodtotem, who transformed and became truly fel versions of themselves (they are also not friendly at all in the slightest and I’m pretty sure we wiped them out). Regardless, we have been shown that there are Tauren who don’t care about the Earthmother and are happy to desecrate the land.
Pandaren… I can’t find a solid reason to not have them, other than the typical nature worship stuff. Our playable pandaren are canonically from the Wandering Isle. Fel magic is just another adventure for their supposed bred-in wanderlust. Is it a great reason? No. Should there be groups of NPC pandaren warlocks? Absolutely not. Could the player be one? Yeah.
Zandalari Demonaics have precedent in the lore, and they were originally meant to be warlocks when they were revealed. However, this was scrapped; I’m not sure if there is an official reason, but, I imagine it was due to class balance, considering they could become every class at the moment save for the Hero classes.
There are Kul Tirans who have fallen under the influence of the Old Gods. I can’t find a good reason for them to not have unsavory fellows in their ranks. I mean, the same reason you can find for Stormwind warlocks, you could probably apply to Kul Tirans.
In essence, I believe the majority of these new races can feasibly have warlocks shown in-game and have it be compatible with lore. However, my only exception here are the Draenei, both versions of them. There should be absolutely no representation of allied draenei warlocks, in order to preserve the lore, the flavor of the race and to preserve what respectable lore we do have for them. However, I think it’s perfectly acceptable for the player character to be one.