EDIT: I'd like to reiterate the difference between 5.3 and the proposed post-SoO crap:
"Giving them something to do isn't the same giving them a reason to go there. Reworking Ashenvale in a post 5.4 patch as you describe sounds pretty lame. After fighting a massive battle to remove the most hated man in Azeroth with an expansion's worth of buildup, you are sent off to do chores... in an area which is even more optional than 5.3. The Barrens/Durotar stuff at least pushes the story towards the climax and acts as a setup for how the invasion of Orgrimmar will happen."