Personally im only against high elves as a seperate race is because theyre a bit redundant from a game value stance (not an rp one).
What i really want them to do is scrap the faction divide and then restructure the race selection.
So the splinter races would fall under one category and then you select the one you want.
Like you would pick human, and then kul tiran.
If they did that, they could easily throw in some other racial tags like wildhammer and high elf without any more effort needed or counting as a new thing.