Quests is vastly better now since cata. This is coming from someone who got loremaster before and after the changes.
Yeah, I did too. leveling is smoother now and much quicker but I hate the looks of the zones that were affected. I also hate loosing South Shore as Alliance since I used to love leveling in Hillsbrad (not to mention the old TM/SS battles).
Oh they were never viable for raids. The whole expansion. That is what my warrior was for
An Alliance prot pally tanked MT'd Tidewalker and it was big news which got the ball rolling on the idea of a pally raid tank.
Pallies were super useful for Hyjal trash too. I think they were capable of doing MTing everything except Illidan and his stupid Shears and were in many cases better due to the old CTC and being uncrushable.
Of the comments given, a common one is using ground mounts and really having to travel around the world the hard and long way. But this is one thing that you still have the option of. You say you miss it, but do you ever just run around on your ground mount for shits and giggles while questing outside of areas like the Isle of Thunder? Probably not; you'll use your flying mount any chance you get.
I like to reminisce about the way the game used to be, but in the end I'm okay with the changes (for the most part).