As I have expressed elsewhere, there is ample evidence that Void Elves can convert other Elves into being Void Elves and that former Alliance High Elves are among their numbers. More to the point, there is nothing that says that isn't the case. The option to play your Void Elf as one who has always been dedicated to the Alliance is therefore present.
I note however your important caveat you place in regards to your suggested compromise, giving Void Elves 'high elven' cosmetic choices. Given how often I am told that it is the lore the pro High Elf community wants, I find myself continually unsurprised that the lore always seems to involve the traditional aesthetic of a high elf. The best you will get is a Void Elf that looks like a Void Elf, but used to be an Alliance High Elf and never called themselves a Blood Elf.
However, the aesthetic of the void elves is a direct consequence of their transformation, you cannot separate one from the other. A Void Elf is a thalassian elf infused by the void, not an ordinary thalassian elf who wields the powers of the void as that would make any Blood Elf shadow priest a void elf. Yes, Alleria can switch between her Void Elf form and a normal looking form, but Alleria also came by her powers in a highly unique way that is clearly not replicable (fallen Naaru appear to be exceedingly rare). Void Elves who are created now will be done so using the conversion process demonstrated in the void elf recruitment scenario and during the world quest when void elves turn ravasaurs into void ravasaurs i.e. blasting them with void energy.
Secondly, the Void Elf aesthetic is the point. They are MEANT to look different from Blood/High Elves. Their skin tones are a feature, not an oversight. It is meant to differentiate Void Elves from Blood Elves, with Void Elves representing the variant and Blood Elves representing the High Elf ideal.
Do you have any evidence for this highly questionable assertion?
An interview with a developer?
A quote?
Anything that proves that Alliance High Elves are being denied due to the capricious whim of one man? I believe that if such a quote or piece of evidence existed, it would have worked it's way into this debate long before now, but if you happen to have it I'd like to see it.
What I would like to suggest is that you probably don't have evidence. What you are doing is scapegoating one person and holding him entirely responsible for the decision not to add Alliance High Elves. Not only does this provide a focus for your complaints, but it also feeds the fantasy that when Ion moves on (as he inevitably must) his successor will be more open to adding Alliance High Elves. The flaw with this approach is that it is, for want of a better word, immature.
One big bad man is not blocking this. In fact, far having a deep seated hostility to Alliance High Elves, when discussing the vague idea of what became the Allied race system in 2014 Ion mentioned High Elves off the cuff as a possible sub-race.
Any sentiment that emerged against Alliance High Elves emerged when they were, as they certainly were, considered as an Allied race by the team. They were rejected because they are essentially already playable as a Horde race. To give Alliance players something, a variant was created. That was actually a huge success.
Which should just mean making explicit the fact that some Alliance High Elves can become Void Elves, aesthetics and all. After all, if the lore is what matters to you, what they look like is immaterial, correct?