I managed to fix this for myself today. Right before Legion launch I declined a quest from Archmage Khadgar, when he wanted me to follow him in to Karazhan (Had forgotten all about it) While standing with the 3 frozen worgens I looked up, and Dalaran was still there. "Okay...?" I thought. And then I opened my map and saw a "!" at Karazhan, and thought "why not, Im close, so I'll finish that instead of dealing with this buggy crap."
I went through Karazhan with Khadgar, finished the stages and went through the portal he opened up to the "Legion invaded" Dalaran floating over Deadwind Pass. There I handed in "Hiding in the Stacks" and BOOM!
I was suddenly standing mid-air, with a few guards and the npc I just delivered the quest to. Dalaran, POOF, in thin air.
Scared to move, I tried mounting up, but "Can only use outside" was all over the screen. I tried turning around to see If there was any solution to this, and to my greatest fear I started falling downwards (Mind you this was pretty far up) Luckily I had some goblin gliders and used one to land graciously right next to Ariden's Camp.
Now there the first thing I saw was worgen tracks to follow, (They werent there before) I followed them and the worgens started running. *MIND BLOWN*