Honestly? I hope Blizzard gives Blood Elves those red eyes and any available San’layn/Dark Ranger NPC skins. That’s been a fairly consistent request for some time now.
Going even further than that, if Blizzard is also planning to share Blood Elf hair styles and colors with Void Elves (we don’t know yet if this is happening), then I think Void Elves should share their non-glowy-tentacle hair options with Blood Elves in turn.
I think if Blood Elves get those San’Layn/Dark Ranger options and some of the Void Elf hair styles, they might feel a bit better about the exchange than if they just get blue eyes and some Void Elf beards.