Heres an idea....I get why blizzard disabled flying until level 90 in mop, theyd created an entire new world and questlines to go with it and they didnt want people being able to skip content, they wanted everyone to experience all of it.
But the problem is, when it comes to alts......im on now my 3rd alt to level through mop content, I have already seen it all on my main let alone doing any quests id missed before with my first alt.....so why should I not be able to fly still to speed up the leveling process a bit? one of the things that makes alt leveling so tedious from 85-90 is the fact you have to ride/run everywhere so it takes a hell of a lot longer then it would do if you could quickly fly between quest npcs and the quest locations.
So why not enable flying from 85 in mop for all those who have already had at least one character get to level 90? The argument of wanting people to experience content not skip it is kind of invalid after youve already done it once or even twice isnt it? and itd make the alt leveling process a lot less tedious!