ok, well it appears nobody has read these books... so I have some time now so I'm just going to go full spoilers
First of all, I'll give my thoughts on some of the different groups
ghostbloods:
This shadow group seems to be directly behind some of the assassinations going on. The name is kind of interesting, I don't think Sanderson would name them ghost blood without a reason. I think that they may end up being somekind of antithesis to the radiants. They also may be directed by taravangian... but I think the more likely leader of the ghostbloods is the jah keved bastard. He was the messenger that came to shallons house to meet with her father and they kept talking about how dark and emotionless he was. Plus, a lot of the ghostblood story seems to be tied to shallans family back in jah keved. I think he, and possibly other ghostbloods can wield a dark power, kind of the opposite of stormlight. There is no basis for that in the books, that is just me guessing 
Shallons Family:
Her family appears to be in deep with the ghostbloods. Her father and brother certainly were members of the group, and since jasnah was having her mother watched, perhaps her mother was too. Her brother may have tried to break away though, because her father was trying to have him killed before he was actually killed by kaladin.
Taravangian:
Taravangian appears to be someone who will be very important in later books. Someone who will oppose Dalinar in unifying everybody. I'm curious if his intelligence is somehow affect by stormlight. Perhaps he is somekind of radiant without knowing it? His diagram seems to plot a path that would put him in charge of every country so that he can save everybody from desolation or something like that. I think there is a chance he is tied to the ghostbloods, because they seem to have similar methods, but I think they are different because he has access to sveth, and the ghostbloods are just using random assassins. If you had access to sveth and needed somebody killed, I think they would just use him.
The parshman/voidbringers:
I'm still not entirely sure that the parshman are the voidbringers. They certainly brought about the everstorm when they turned in the storm form, but I'm still not convinced. I remember jasnah finding a picture of a voidbringer and it was a chasm fiend...
sveth:
Well, sveth is reborn now and no longer has to do the will a taravangian and he has nightblood. He is being set to bring "justice" to the shen who didn't believe him. I think we will find him capturing all the honor blades... perhaps he will be able to combine all that power to confront the radiants at a later date.
Adolin:
I think Adolin is actually in a position to be the most interesting character in the next book. He is poised for huge fall. He murdered sadeas in cold blood and didn't tell anybody. He is in love with Shallon, even though it seems she has a much stronger bond with kaladin so he is primed for a break up there. He is also the only person in his family left that isn't a radiant. So, I see Adolins going down three different paths in the future.
1. Super dark path. Shallon breaks up with him and it is found out that he murdered sadeas. Dalinar is forced to order his execution. He runs away. Broken and abandoned by people he loved, he falls further down the dark path, possibly joining the ghostbloods or another group like that to kill kaladin.
2. The rough path. He admits he murdered sadeas which prompts shallon to break up with him. He is imprisoned, but eventually set free and allowed to continue fighting. His presence is lessened and he is resentful of others.
3. The redeemed path. He admits he murdered sadeas, but shallon sticks by him, choosing him over kaladin. He is imprisoned and tried, but in the end he is freed. He is either given the honor blade or becomes a radiant in his own right.
Wooh, thats a lot. I'll write some more later.







