People on forum were discussing how to bring players back to wow. I think removing Pathfinder achievement to fly and bringing back max level buying fly model will be a good start.
I can't remember how many returning players get turned down by this absolute bullshit requirement. A returning player has to farm previous expansion rep and achievements to unlock flying in those areas. How can this encourage to bring back any players? And it certainly doesn't help material farming for professions or world quests etc.
Max level buying to fly worked fine from TBC to MOP, there is absolutely no reason to change it. And Pathfinder achievement itself has no meaning or depth behind it, it is just flying gated by reputations.