Flying doesn't take away ANYTHING from the gameplay. Seriously, why are people spouting nonsense like that?
I was around when Azeroth was a no-flying zone, and guess what...PEOPLE DID THE SAME F-ING THING THEY ARE DOING NOW ON FLYERS!!! We see each other pass by, we go on our way to where we want to be. People didn't just stop and become bestest buddies because we were travelling slower and on the ground...
When some poor bastard came and was pvp flagged, he'd get ganked unless he remained mounted and tried running for it. The ganker would follow and keep trying since gankers are like that. If someone lands today and is pvp flagged, the ganker simply waits for the player to dismount, and then goes about doing what he does.
Them removing flying won't cure your nostalgia. The gaming community has changed, DEAL with it.