The funny thing is that if the world is designed around no flying - then it's not coming back, at least not in a quick way.
On top of that, if subs plummet due to this, by the time they get around to patching it back in, the damage will have already been done.
And before you know it, this expansion too, is a failure.
Removing no flying is essentially just adding another timesink into the game - much akin to dailies and rep in Mists.
This just removes the shortcuts, as well as the convenience, which forces you to play for additional time and maximizes your subscription versus the content.