Yeah another way to get high elves: purify the void elves of their corrupted state and turn them back to being outwardly high elves somehow.
Alleria looks just fine outwardly, she wasn't hit with the emo hair and skin so theoretically there should be a way.
Blizzard had a great opportunity: Instead of the void elf asspull they could have introduced Nightborne to the horde and High Elves to the Alliance.
Now that they blew this opportunity however, another way should be found.
Edit for clarity: No new race is needed just a switching option for the void elf race which they can utilize to veil themselves to look like regular high elves.