I doubt that, only because for it to be completely legal, it would have to be seperate from WoW in every way, meaning they would have to build the entire game from the ground up (not happening), and it wouldn't have to infringe on any of the rights or intellectual properties of Blizzard, meaning none of the names, places, characters, etc, could be the same.
Therefor, this is impossible, because even if something like this did happen, by the end it would turn out to be Runescape, because they'd have to make their own MMO from the ground up. GL HF.