...is my theory that Rand and Moridin didn't actually swap bodies, but that they actually merged. I have seen stuff in the notes that indicates that this wasn't RJ's original plan, because his original wording of Min's viewing suggested they would merge and then separate again (RJ put a question mark there). But he did change the wording of the viewing, and my theory was that they merged but that Moridin's consciousness was in a state analogous to someone whose mindtrap had been broken. He can hear and see and feel everything that Rand does, but he has no control over Rand's body, and he can't die until Rand dies. (And of course, death/oblivion was what he wanted more than anything else.) The viewing and the mindtrap were both introduced in ACOS.

This theory came about because of the idea that Slayer was a prototype for Rand/Moridin, but there were details in the notes to make me question that too, mainly that RJ did seem to imply (without explanation) that the balefire incident caused the link between them. Since neither Luc nor Isam can channel, their merging had to come about in some other way. But again, it's possible that RJ changed/developed his ideas on this as time went on.