Auric is not neutral despite what you saw in Quel'danas. Many NPC's of the opposite faction are flagged as neutral during specific events so as to prevent players from attacking them during that event. Dark Ranger Vorel is flagged as neutral in WOTLK Dalaran. That doesn't make her a neutral NPC. If you see her elsewhere she is hostile to the Alliance. Grand Magister Rommath is flagged similarly in the Quel'danas event but no one would mistake him as neutral or friendly towards the Alliance outside of that event.
Auric is the same way. He's neutral during the Quel'danas event because that event requires him to be flagged that way. If you see him outside of that event, he is hostile towards Horde players. He is not neutral, and he already fulfills the position of representative for the High Elves who aren't Horde.