Unfortunately, these "good" arguments come at the expense of faction identity, which Blizzard have iterated on several occasions recently that the faction divide is integral to WoW. Factually, yes there are some high elfs aligned with the Alliance. Lore wise, they are so few in number (confirmed on several occasions by devs, despite what you may think in game). Gameplay wise, they are the same as blood elfs in nearly every aspect, and as such their inclusion as an AR would undermine the faction barrier.
"Good" arguments don't matter if they ultimately undermine core features of the game. And on top of that, Blizzard has very clearly stated that blood elfs are the continuation of the high elven story. Adding high elfs to the Alliance would undermine this core feature of the Blood Elfs, WHO ARE the main high elven society in WoW today. However, some folks don't seem to care about this, as long as they can have their light skinned elf fantasy on the Alliance.
Lastly, Ion was not factually wrong. DK blood elf = blue eyed elf on the horde
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The difference is the other AR requests don't cross faction boundaries like high elfs do. So your argument is invalid.
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It's possible for void elfs to never get any high elven customization either. You really are clinging on to Afrasiabi's comments for dear life. It's possible for high elfs to defect from the Alliance. It's possible for high elfs to be killed off. It's possible that we may never see another high elf NPC again. ANything is possible, like Alex said. You get my drift..