You are confusing Beledar with Naaru spacecraft, when they are decisively different as far as we can tell. Still, maybe they do have a crystal. Still, the Arathi have to be involved in this expansion since they were conceived to fight in the battle of light and void, that's their purpose. I think it'd be a wasted opportunity not to see them as antagonists who NEED to circumvent Haranar to pass up into Quel'thalas, and if the Haranir don't want them to pass for whatever reason, or they need to destroy something to pass, then there is obvious conflict. I could see Faerin being involved in trying to diffuse the tension, and navigate the crisis. Yet you can't hold zealots and crusaders back, if the Haranir get in the way and plant their feet on the issue, they would have to fight.
Imagine them trying to take the Dawnbreaker up and through to the skies of Quel'thalas? That'd be dramatic, though it'd require some huge tunnels. I could definitely see them needing to damage some roots for passage. (These are the ones in the roof of Azj Kahet)
