Blizz is often criticized about the very poor "training" given to its players for all manner of things....in particular dungeon and raid aspects of the game.
It would be very simple for them to implement a "guided tour" of dungeons etc as a "ghostly observer" with a "preferred" group (even as a quest) and show key aspects of the instance...hell they could even charge some G for it....it would certainly help new players come to grip with dungeon/raid mechanics and it would add another Gold sink for Blizz.