People are complaining that anything other than the quest objectives is a waste of time, and the people who struggle to avoid tree roots or to run past mobs without aggroing them all and being dismounted would probably struggle to deal with airborne mobs or anti-air turrets. This is especially true if the air obstacles are set to ensure that flying has no advantages over ground, in fact the air would have to be much more difficult to navigate due to the quicker travel speed and ability to travel in a straight line.
It's really hard to take you seriously when you come out with rubbish like this.The only thing keeping flying from being something amazing is a petty, unthinking hatred based on false premise and ignorance.
Personally I don't think it would be worth whatever time it would take to create two sets of content perfectly balanced to ensure ground and air are equally viable, especially not if the engine needs a revamp to make 3D movement and combat better.Everything costs dev time. The question has always been striking a balance between what the devs want to do and what the players are willing to accept. Right now no-flying is being forced onto everyone whether they want it or not. That's mitigated by the game being in a better state than it's ever been, of course, but that doesn't mean it couldn't still be handled better.