Assuming void elves only exist because the decision was made beforehand to give nightborne to Horde? There’s no evidence the rationale worked out that way. It’s just as likely that void elves were an opportunity to give high elf fans something by allowing the thalassian model to be playable on Alliance while not violating the fair-skinned Tolkienesque fantasy that Horde blood elves have claimed ownership of for years.
Nightborne also aren’t Night Elves. Their models are a bit too close to the night elf rigs for my liking, but aesthetically these guys are supposed to represent everything the night elves detest and reject. The magic-oriented society is a painful part of their history, which is why they have gone a completely different direction and based it almost entirely around a theocracy and a druidic culture. Culturally, Night Elves and Nightborne couldn’t be more different, making them natural fits for the Horde (seeing as how the Blood Elves were already there).
They have said many times that they do not want to. Last time Ion talked about it he said that his understanding of a high elf was that it was just a blood elf in terms of aesthetics and culture. The ones that exist today are just NPCs. There are Mag’har orcs who are part of the Alliance but there are very good reasons why those shouldn’t be playable either.
The problem is, no matter what excuse the devs give, it will never, ever, ever be enough for the high elf fans.
If someone asks for a “compromise,” and they get it, then it’s not a compromise; that’s just them getting what they want.
High elf fans don’t leave room for compromise. They specifically want blue-eyed blood elves on Alliance. They want them to be paladins. They want them to have the WC2 tattoos. Giving them the thalassian model sans the fair skin color and the paladin class should have been a great compromise, but they don’t see it that way.
They don’t want compromise.
Fan-fiction, by definition, has to originate from concepts developed by fans.
New lore developed by the game’s writers is official lore, not fan-fiction.
The determination on whether something is fan-fiction or not has nothing to do with your personal acceptance of the lore.