Should it? Probably, for Blizzard's sake. Leaving Draenor without flying mounts is bound to create more QQ threads about how people are too lazy to navigate the world and who find it too hard to use their map. It'll get to a point where Blizzard will get sick of it and just be like "fuck it, let these babies have their flying mounts". Come next expansion though the new thing will be "oh the world is so flat and plain they should've put more detail into the environment". What for? you're flying in the air on your 310% mount ignoring all the detail of the environments anyway. We might as well just have a barren wasteland with a few rocks and hills here and there to spice it up a bit.