What connection to WoW does "Cataclysm" have then, for example?
Sargeras will be free when the expansion that centers around him comes. That could be 9.0, 10.0, 11.0, 12.0 or basically any future expansion. The only nonsensical thing here is to assume what's nonsensical and what is not in a fantasy franchise made my people you clearly do not understand.