I find it makes an interesting viewpoint to think the character from their ends: How are they going to die? - Because in fiction, the death of a character often gives its live ("life") significance, meaning or relevance. How is Theon going to die? Assuming that Jon Snow does not actually die: I'd guess that Theon gets executed by Jon, as Jon finds out about Theon's former betrayal. There's hardly a way Jon could forgive Theon, even though he has already suffered that badly. - This way, the entire Theon-Storyline would be ultimately about Jon, as he is forced to make a morally complicated, if not impossible decision. And it fits well the overall idea in ASOIAF that redemption and punishment are fleeting, if not futile.
