I think my biggest problem with the lack of flying is that as nice as it is for treasure hunting at first I find it actually has a negative impact on my sense of exploration in the long run. I've been done with all the quests in WoD and most of the treasures for a while now which is kind of the only major reason to go out into the world this expansion besides the daily apexis crystal mission. One of the things I liked in MoP was that when flying to a location I would alter my own flight path to be on the look out for rare spawns who on the whole were far more interesting and a lot of them had valuable items (elixir of ancient knowledge, pets, bags of goodies, the 5.1 ones gave more of the 5.1 currency along with dropping pvp items, and eventually the zandalari had mounts/rep tokens/more bags of stuff).
Now to be entirely fair not all of that is strictly the fault of no flying. I've been complaining about the lack of max level content for a while now, but it's only gotten worse as the days continue on, especially in regards to stuff that gets you out in the world. The removal of daily quests is one of those baffling swings in the complete opposite direction, all they needed to do was remove epics from the reps and put a little hub in every single zone, not many people were really complaining about reps like the Anglers/Cloud Serpent/Tillers, it was more of Golden Lotus and Shado-pan. That aside though, even if there was stuff to actually do out in the world I think the flight paths are too good now. There is a FP right beside almost every major point in the world now so I find myself barely mounting just in general.