As a lore pedant I can’t see it happening either . It would be problematic for a couple of major reasons.
One of which is that would drive the ‘Enough with Elves!’ crowd absolutely insane. I could actually see that perception for once, We’d have Sha’dorei, Sin’dorei and Death Knights, We already have another Hero class so exclusive to Blood Elves in Demon Hunter. If Dark Rangers were released as a Hero class, that would seem kinda unfair on the other Horde races, you’d have two types of living Elves, two types of Undead Elves, and one type of demonic infused Elf.
The other problem is lore… Technically there should only be Female Dark Rangers. Nathanos was created differently, and only Female Elves can become Banshees, male Elves become Spectres (Or as Blizz apparently jokingly called them ‘Manshees’.
Reason that is problematic is that Banshees can possess people, Spectres can’t.
So logically only female Elves who have died can be Dark Rangers, as you need to possess your -own- dead body, and Spectres can’t.
Now, given the current climate at Blizz HQ can you see them being in a hurry to release a Hero class only playable by one race and only females, especially the race some people find ‘sexy’?
Of course, this is Blizz, they’ll probably fall over and wake up having forgotten their own lore anyway!
The last is a trifling one, but is bound to annoy the perpetually annoyed.
They’d have three language slots, Thalassian, Orcish -and- Forsaken. I know, petty, but some people would get annoyed, I bet you.
I think the red eyes customisation is your best bet.
And as Mentioned…
I’d forgotten that until you reminded me, but yeah, they were definitely in the data files…
So all hope is not yet lost!