I left WoW on the day before Legion launched (specifically due to the flight situation). As it turns out, that was probably a pretty wise decision considering everything said about the expansion.
Anyway, I will most likely return for 7.2 and (as long as a future patch does not feature a no-fly zone) stay subbed for the last half of the expansion. By then all of the various grinds will probably be reduced to about nothing, so it will probably be more fun anyway.
But if they bring in a new no-fly zone I will be out again though... maybe for good, since I have found other good games to play in my absence that will do just fine.