After finishing the starting zone on a new alliance DH, I completed the Illidari We Are Leaving quest with Archmage Khadgar and instead of being ported to Stormwind, I was ported to the Great Sea northwest of Western Plaguelands and Tirisfal Glades. I was unable to mount, so I had to just die to fatigue and resurrect at the Faol’s Rest graveyard site in Tirisfal Glades.
Similarly on another alliance character, I was ported to the Forbidding Sea outside the Badlands taking a portal from COT to SW (added to another bug report). Possibly other SW portals are bugged.