I am unable to start the questline after becoming Neutral with the Netherwing. I have had Artisan riding for a long time now. Mordenai doesn’t have the quest Blood Oath to the Netherwing.
That part of the chain (and subsequent dailies) have not been released yet. Most likely will come out next phase with T6.
But I’m seeing people on netherdrake mounts on my server, quite a few actually.
Those are season 1 gladiator netherdrakes. Not the ones from rep.