I'm not sure why Dirk was let go... Who was it at AMD that said a while back that AMD was going to downplay core improvements and that future performance improvements would be made by adding more cores?
It is no secret that AMD has not been firing on all cylinders for the past few years. I would think that Dirk would have to accept some of the responsibility even in his role prior to CEO.
And, maybe it was Dirk who was the one who talked the board into selling off the Imageon business that provided graphics to cell phones. Maybe the board is now seeing that as a mistake. It's all conjecture so its anybodies guess.