I've seen Redin, the bastard son of the former king of Jah Keved suggested as a potential Dustbringer. He's obedient when killing his father, despite what it would mean for his future to be known as a patricide.
I very much enjoyed it.
I did not predict who Dif was. I thought that Biblioden would be revealed to be Alcatraz the First who had turned his back on Talents and Silimatic technology after the destruction of the Incarna. Breaking a language fits the controlling knowledge idea. And breaking time could let someone live forever. It seemed to make perfect sense. Unfortunately, I think there was enough evidence in the books to disprove my theory.