Do you think that Morhaime will announce another annual pass during the BlizzCon opening ceremony tomorrow? With MoP essentially complete and a new expansion about to be unveiled (but probably not released for 6 months or more), the timing seems ripe to get people to commit to another year of WoW.
They could package it with a free copy of the D3 expansion as it should be released around April 2014, along with some other standard goodies (WoW beta access, mount, Hearthstone stuff, etc.)
Seems like a strong possibility...