Malikoi generously offers to buy Dalaran's old location over on the forums, and says he plans to create a new city, complete with flight path, graveyard, and even an arena. It's not like the Kirin Tor are going to need it any more, right? They're moving the magical city of Dalaran up to Northrend, so Malikoi should be able to pick up the old land.
Bornakk, however, says the Kirin Tor are not selling the land, which of course begs the question: what are they going to do with it? They could only take part of Dalaran up north, and leave part of it there in the Alterac Mountains (to serve as a new quest hub for lowbies, perhaps?). Or maybe Dalaran will have to fly up north under duress and what's left behind in Alterac will be the remains of some battle the mages had to fight?
It will be kind of a shame to not have that purple dome there any more (and it would be cheating if Blizzard just left it there when they've already told us the mages have made the decision to move the whole city). There's a lot of wonder to be found in Azeroth, but I can't think of any other experience that has matched up in exactly the same way to turning a corner from Hillsbrad and seeing a gigantic pink dome in the middle of nowhere. Hopefully whatever replaces it will inspire that same sense of magical amazement.