As someone who has personally known several Blizz leakers, this information is probably pretty accurate. People fail to understand that these leaks come from early or mid-term development, where rewrites and reimagines can happen (and a lot of the time do happen, especially when Blizz is aware initial plans became leaked).
Imagine if the early WoD concepts were leaked and no one ever knew they were actually confirmed concepts. You'd have leaks saying shit like GARROSH MAKES A NEW HORDE OUT OF GNOLLS AND KOBOLDS and people would be like "lmfaooo fake leak fake leak lol fag".