For what its worth I think you can land anywhere you want with them, its all to do with the way Azeroth is set up.
Stormwind is effectively an illusion, towers are 'floating' in space. When you come in the FP steers you through one way so not to shatter that illusion. If you were to arrive, say, from another direction you'd see that SW was built like a movie set. And like a movie set it only works when the camera is in one position.
However, Outlands are built in a new way, from what I've heard on the forums, the buildings are visible 360 degrees, so = flying mounts. Imagine being able to land one of those mothers in a battle!
I could be wrong tho. I blame the instance if I am lol
And if you think u are slow at levelling .... try being me

(Thinks) They'll be some sort of uber armour / mount thing by the time I reach L70. New Level cap ! L80. New instances! Mounts that go UNDERGROUND! etc etc etc