Just saw this over at reddit, also the MMO-C front page, Keep in mind this is all speculation!
Edit: On the MMO-Champ front page as well, still speculation as it hasn't been confirmed in game
I mean I can only imagine this is going to be part of an original quest line as a pre-Legion launch event. Like we're battling Legion forces below, around and inside of Kara? I'm more than positive this isn't a permanent position for Dalaran as there's screenshots from Blizzcon with Dalaran over the new zones
Either way, if this is happening before Legion bring it on! Combining 2 of my personal favorite locations in the entire game, I'm sure more can agree!