They say they don't have plans for another annual pass. Against this is the most certain disappointing sales figures comparing RoS with D3, proving it's a major failure as a game, as not even the expansion could bring people back. Another Annual Pass could ease this shame. BUT, since the AH is going down I see no real reason to attract more people other than marketing and it's a weak one.
I agree the new expansion for WoW is coming way sooner than most expect.