To me that looks like they try to force people to play, which is understandable and some would argue it's good, but incomplete. I would agree you get faster flying speed if you meet prerequisites, but there are people who dont spend their entire day playing games, so yes they dont have to have as good stuff, but flying as basic, I think, should be there for them.
Yes, they saw people have "no endgame content" and thought "oh wait, lets make them quest". IDK, I agree withj Nikco, flying should've been there. Like, yes, it ruins world pvp, i know, but these who want to world pvp can stay on ground, let fly those who dont want world pvp. I mean, everyone uses flight paths, right? Wont be surprised if in Legion they say "oh wait now you can ride a cart as automatic moving but you have to defend yourself. oh wait you dont want them to kill you? well they want world pvp so f you." Just my point of view.
Or even if they put prerequisites even for basic flying, then it could be in more ways, not just questing. There are people who love questing, they should have ability to earn it through quests, these who love leveling alts - through leveling alts, these who love pvp - pvp, pve lovers - pve. And it shouldnt take too long to get basic flying (like 150%? was lvl60), but you have to grind etc (what hardcore people want to be rewarded for) can fly faster (like 280% was at lvl70...)