There isn't anything spoilerific as Sanderson is being very tightlipped with details about A Memory of Light. As he should be.
The two biggest pieces of information that came out is that Sanderson has requested that Harriet NOT attempt to publish the outrigger trilogy that Jordan previously discussed (it would resolve the Seanchan plotline and be very Mat-centric) and a little bit more about the Asmodean-killer reveal.
Regarding the Mat / Seanchan trilogy:
About the prequels/sequels, there were no big news. Sanderson 'strongly advised' Harriet not to have them written - but if she thinks otherwise, he wants to write them . . . According to Brandon, it's the three outriggers Doherty is trying very hard to convince Harriet to have written, and the motive is quite personal: RJ sold him hard on the ideas for this trilogy and Doherty is apparently the biggest Mat Cauthon fan on the planet, so he wants these books written very very badly. Brandon would still prefer they were not. Harriet doesn't want to think about them for the moment.
About Asmodean, he gave a few more details but no huge news. When he decided that after all he would reveal the killer in the books (which he originally didn't intend) then got sick, Jim took no chance and took time to write down an extensive note about the murder, explaining very precisely and in many details what happened and what lead to it. He had not decided where this could go (or even if it really would be in the book or he would publish the note after the paperback of AMOL was out), so it was left up to Brandon and Harriet to decide on the character who could reveal some of this, and how and where in the book.
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