Imo what is WoW missing is the feel of an open dangerous world.
The perfect example to this would be:
Going to MC in vanilla by walking on a huge chain above a pit of lava and going deep to Old Ironforge where there is a rocky path that has invisible walls to make sure that nobody will fall in the lava.
And in some cases it was the invisible walls that took that feeling away and in other cases it was ofc flying.