I sincerely hope leveling is done after WoD. There is absolutely no point. There is plenty of leveling content if people like to level. Gear and other progressions can take the place of leveling.
Take Zul'Drak for example. how long did it take to design that zone? There is literally nothing to do other than 2 hours of leveling quests. It pains me to think of how much dev time was devoted to creating such a pointless zone, probably at the expense of a raid tier.
I fully support the creation of new zones of max level content. Imagine an expansion where the whole continent has max level stuff.
bottom line: leveling sucks