What if the next expansion is something completely out of left field that has nothing to do with the old WoW or WC3 villains? Instead it is another completely new adventure with new lore and new enemies. Like Pandaria (even though Pandaria was mentioned in WC3), the driving force of the expansion is something that no one expected or desired, but was still feature rich and highly enjoyable.
Would that the final straw for you? Would you quit WoW and never come back?