I propose that we will learn that the crux of the Ancient Agreement with the Finn goes far beyond the trading of wishes and knowledge in exchange for memories and experiences. I think we will find the primary reason for the link between the worlds has to do with the imprisonment of the Dark One. I think the Dark One's prison is somehow metaphysically attached to the Finns' world, and they had some role in the design, construction, or positioning of his prison, probably from the time of creation. It may be due to the proximity of the Dark One's prison to the Finn world that questions dealing with the Dark One one have dire consequences.
I am almost sure we will learn that a portal to the Finns' world exists at, or very near to Shayol Ghul. My certainty lies in that i think RJ foreshadowed it in KOD when Tuon mentions a childrens tale:
"How many children's tales do you believe? Do you believe that if you sleep on Old Hob's Hill under a full moon, the snakes will give you true answers to three questions, or that foxes steal people's skins and take the nourishment from food so you can starve to death while eating your fill?"Then Mat remembers Old Hob is another name for the Dark One and he thinks that her descriptions sound very close to the aelfinn/elfinn. So I surmise Shayol Ghul = Old Hobs Hill and its tied in with a legend related to access to the finns world, hence my theory.
- Knife of Dreams, Chapter 10
It's pretty well established that Mat will be captured, at least for a time, by the Finns during his attempt to rescue Moraine. I think Rand may learn of this access to the Finn World, and via the swirling colors will get a glimpse of Mat's predicament and of a living Moraine, and this may be the final impetus to send Rand towards Shayol Ghul. Rand knows he needs his horn sounder and Moraine as per Min's viewing so he may launch his own rescue attempt. It may be via another encounter with the Finn's that Rand learns the final piece of the puzzle on how to defeat the Dark One and/or re-construct his prison.
I thinks its interesting to note in Norse Mythology Loki is punished by being bound and held until the last battle, and its widely known Mat is tied in to the Odin/Loki legends of Norse Mythology. I know this doesn't mean Rand will come to his rescue, maybe Mat will just flash his winning smile to one of the female-like Finns, those smiles are supposed to always work, right?
Now that I think about it, I don't think we'll get this close to the last battle in TGS, but we should get some part of Mat and Co. entering the Tower of Ghenjei, and maybe further revelation about who the Finns are.
Not so ridiculous after all?