Speaking with Strategy Informer earlier today, we asked Kosak whether change on this scale was viable as a long term solution.
"It's definitively a huge undertaking," he said.
"There was a lot of content in this expansion, and certainly it's not sustainable to say every couple of years we'll have another Cataclysm-type event to keep things fresh. But if you compare how the game plays now to how it played six years ago, I think we'll be happy for another couple of years."
Cataclysm, Blizzard's third expansion for World of Warcraft, is due to go on sale at midnight tonight. You can read the full interview here.