Mounted combat with the outpost perk in WoD Nagrand was awesome and the Legion Paladin class perk to for an hour of mounted combat and environment interacting is amazing.
I would happily give up flying if they let me always fight, mine, and click items without the 2-3 second re-mounting process.
Not going into the whole should we fly or not, but what would you think if Blizz said no flying but mounted combat for all?