MMO-Champion is reporting that Blizzard has trademarked the phrase "Mists of Pandaria". Apparently the timing and technical details of the trademark are leading people to speculate that this will be the title of the next WoW expansion.
It could be true. A mysterious continent, maybe magically hidden until the Cataclysm revealed it, would be an interesting setting for an expansion.
I don't think Pandaren will be a playable race, though. Which faction would they belong to? What race would the other faction get? If anything, I thing Blizzard should go with making them a neutral race, maybe one that both the Alliance and the Horde are courting for favor.
Another argument against a Pandaren expansion is that it would not be "epic" enough. The last two expansions have been the Lich King and Deathwing. Pandaren are simply not in that league.
While this is a good point, I wouldn't mind a quieter expansion. A little less world-destroying threats, and a narrower, more detailed focus.
So is Mists of Pandaria the next expansion? I have no idea, but Blizzcon this year should be very interesting.