Stop bitching their argument here is actually pretty solid. Though flying is very comfortable it severely disconnects you from experiencing the world, since you skip most of it. Thus their idea to have people properly "experience" the world content before making it just a background wallpaper through flying is a decent way to deal with it.
However the time needed before you can unlock flying can be argued as (way) to long. Since after half a year of world quests everyone who has played for that long just wants to get things done and doesnt really "experience" the world anyway.