I'll strive for brevity here:
There is an argument that delaying flying makes the world feel "bigger and more threatening" and apparently a large percentage of the WoW population agree with this sentiment.
Here's the flipside: I get my "bigger and more threatening" feel from great artwork, challening content and a good story. Delayed flying is just a waste of time, and I suspect most of the people in favor of it don't spend over two hours a day commuting by car or train to an office.
What happens is that people like me that work 60-70 hours weeks think "fuck this..." and we unsub until 6.1 comes out and we can get what should have been in 6.0.
I won't waste my time in a game. There's enough time-sinks in real life. Including commute times. If I'm grinding mobs for several hours, which I'll admit happens sometimes, I'm doing something. Even if it's functionally pointless, it's relaxing. Cathartic. It's unwinding from the real world. Hitting auto-run and occasionally twiddling the mouse to stay on the road isn't doing something.
If you value your recreational time so little that you think running along a road for 10 minutes between zones is a useful application of your time, power to you. Just don't inflict it on the rest of us. Just stay off your flying mounts until 6.1 and feel proud of yourselves.