Remove the following things:
All ability to teleport to Dungeons, Make everyone ride there.
Remove Flying mounts from Azeroth
Remove all high level guards from low level towns and villages
Buff Dungeons so that you actually need to play your class properly
Remove at least 50% of wind riders and graveyards, get the traffic back on the roads
Remove Ability to teleport into Battlegrounds, make us go to battlemasters as in the old days (just make more of them to avoid griefers).
Remove a lot of phasing as it ruins immersion when you chase someone and they suddenly vanish.