If Blizzard really wants to stop the high elf controversy without making high elves playable, it should focus on promoting the void elves, not on giving reasons why they can't give us high elves.
Void elves are poorly-thought, badly developed copouts, but they do have potential (and nothing else). I can think of many ways to make them more palatable to the high elf crowd
without giving them high elf skins. The problem here is that people will be way more unwilling to give them a chance now than they were before velves were released (you can check it out: the high elf requests exploded after January 30th. Until then, most high elf fans were still hoping void elves would turn out to be good).
The big problem is: everything points out to void elves being just a gimmick to allow players to be "Alleria-like elves" (while looking nothing like her). There's not a single interesting void elf interaction so far in BfA, all their cameos are just as some generic team of rangers following Alleria around. There's three void-related zones, plus a 4th one dealing with dark magic that may or may not be void, and yet you don't see a single void elf camp or interactable NPC. (I hear Umbric has a role in the Alliance campaign in Vol'dun and later becomes a follower, but I'm still waiting for details to judge it.)
Void elves desperately need some depth. I say that Blizzard must:
* Expand Telogrus Rift, putting events/gossip/interactions there that explain the basics of void elf lore (like the most obvious questions of them all: can new void elves be created? How are new ones transformed? Why are so many elves going there to become abominations tied to corruptive dark magic?)
* Provide a proper core cast of void elf NPCs. At the very least, make a representative leader for each class. I'd take some known blood and high elf characters and turn them void elves. My choices would include Lyria Skystrider and Priest Ennas (the priests that try to preach against the Horde in Silvermoon), Summoner Nolric (only high elf warlock known), Taela Everstride (from Allerian Stronghold) and Theloria Shadecloak (from Allerian Post in Terokkar) as examples of elves I'd turn void to fulfill a core cast.
* Make high and void elves have tied roles (much like Worgen/Gilnean are tied together, but only worgen are playable). Make the two races cooperate frequently, share camps, and sometimes buttheads among themselves. High and void elf lore would intermingle from now on, and be ultimately undivisible.
* Put the void elves front and center of at least one major storyline in BfA. As the only Legion-related allied race that had no development in Legion, they really need immediate attention.
Aside from all that, expanding void elf customization would be nice to try to draw in a wider range of personal tastes.
I'm not talking normal skins here. Get some of the fan ideas behind high elf customization and apply to void elves. Personally, I think they need white-grey and white-purple (not bluish) skins. I'd give them more hair colors, like silver-blue, deep red, pitch black. And I'd give them warpaint, in colors such as red, blue and violet.
These suggestions are the very same that have been circulating in forums since November 2017. If Blizzard had paid more attention to them, maybe all the high elf talk would have never gotten so out of hand.