The problem is one that Blizzard has acknowledged - the power reset. My character has saved all of creation something like three times: Algalon, Lich King, and Deathwing. Saved. The. Entire. Frigging. Planet. Three times. But at the beginning of MOP, I couldn't fly, and there were factions on this new island who were not impressed - even a little - with the fact that I had saved their very existence three times already. I had to go from being a level 85 hero and conqueror to a level 85 noob again.
Like I said, Blizzard has acknowledged this as a problem. If they let us fly at the start, the gankers won't be able to gank us. And for some reason, Blizzard likes it when the gankers gank us. It's just too convenient for us to skip things if we fly, from their point of view. Hell, for MOP they added blue shells that'll knock you off your flying mount just to help the gankers gank us easier. (Joke's on them, I have engineering wings and camo + the camo glyph.)
Now if it were me, and you were right about Xoroth, I'd let people fly... and then seed the skies with demons that attack people less than level (new cap). (Even though I personally would hate that.)