I am not a lawyer, I work for an insurance company.
Whilst people wanting something helps Blizzard decide on a course of action, it is not the be all and end all of discussion. Were everything subject to a popular vote, we would all be flying right now in BFA and would have been from the moment we entered the expansion, or at least those of us who had deigned to return from WoW Classic's seventh anniversary celebrations would have been flying.
It is true Blizzard is not blind to what their playerbase wants, the forums do serve a purpose and are read. But sometimes a request has further ramifications behind the personal gratification of an individual player or even a group. As is the case with High Elves.
I believe it is certain that High Elves were among the first Allied Races considered, maybe even the very first. Ion's comment in early 2014 spitballing ideas about sub-races that became the Allied race system had him talking about High Elves and Mag'har Orcs, two very popular requests. So they weren't blind at all. They knew.
And despite that, Alliance High Elves were rejected. And they told us why they were rejected, the reasons I knew they would be rejected on. That as Blood Elves are High Elves, High Elves are merely duplicate.
For all the bad people say about Void Elves, at least they are a credible variant.
And Daz, stating Allied races will be released in cycles is incorrect. Check the Q and A for June 2018
https://www.youtube.com/watch?v=4AVTzRatRcY
Second question about two minutes twenty seconds in where they are asked whether Allied Races are just a BFA system.
Ion responsed we will see Allied races in future, but it's a centerpiece of BFA as part of the story is gathering up allies for our war with each other and that it will be cool for meeting awesome new allies post BFA and bring them in.
However, after praising the tool, he added a qualifier
'that said, I do want to note that we're not thinking of this as something that as we get past Battle for Azeroth we need to check off...like alright what's gonna be the allied race for this patch? We don't want it to be going down a road where five years from now there are thirty races to choose among and we're just kind of coming up with things not because it makes sense for the story but because we feel like we need to add new Allied races...'
In other words, this is not the first Allied race cycle and that as soon as it is done, they are going to go back and start again and add other variants. They are pushing it now because it is such a core feature of BFA, but after this it looks to me that Allied races are going to become rare and special. And it looks like that to me because that is what they pretty much said.
And with Allied races becoming so much rarer in future, I don't see them blowing it on a choice that is already available in two flavours and which carries so much baggage.