For me the speculation about Odiums champion is the big one, since Dalinar seems set to fight himself.
When Dalinar asked the the storm father who was the greatest of the heralds, after being slapped around by Ishar (average amongst the heralds) despite a whole retinue of windrunners, I instantly thought oh no, Odium will make Taln his champion.
Why wouldn't Odium set it up so that he can't loose? He picks the best there ever was right. We know Talns mind is feeble and since Odiums minions were the ones to break him, they seem like the ones who would know how to make him able to fight again, but for the wrong side.
I'd be interested to hear more theorycraft on this subject.