It was great for the Horde races without qualification, though orcs and Forsaken were best served. Alliance got the short end after having a much more fleshed out Vanilla experience. But the idea of actually moving with the pieces you have and seeing where they'd go was something they've never done after. Even stories where each individual zone is a form of worldbuilding and advancement, Wrath and Mists most of all, are still spacially limited in a way Cataclysm wasn't.
@Das Momo
For a world revamp to be useful for gameplay it either needs to be an ever-green introduction to Warcraft as a setting to fill the gap from 10-50 to the max level 50-60 zones, or to be those max level zones.