re: Kaladin/Parshendi
Given the Parshendi have managed to break from Odium’s influence (perhaps for only a short time, perhaps forever), what if Voidspren could do the same?
Furthermore, what if Voidspren are just high spren Odium managed to corrupt somehow, and when they break free from his influence, they return to their natural state (honour, cryptic, etc…). Whether they can remain free from Odium permanently is another unknown. Perhaps that is why Syl is somewhat concerned about being seen, but not terribly concerned about the spren (and what it might do).
Now, if Parshendi and spren can fall under Odium’s influence, then why not humans (as others have speculated)? Or what about humans (or Parshendi) bonded to spren, if one or the other comes under Odium's influence would both do so? Which makes me wonder if this might have been part of KR downfall….