I'm curious if the letter "naturalizing" Jon as a full-blooded Stark is even going to be worth the paper it's printed on, seeing that... Spoiler: Jon ...damn near everyone who would have recognized its legitimacy is now dead or imprisoned. For that matter, does the letter even exist any more? And, yes, I would agree that Jon really doesn't have much interest in lording over the smoking hole that is Winterfell, particularly since he turned it down quite promptly when Stannis offered it to him. That, plus, by the end of ADWD, he has become quite occupied with the rather egregious problem of possibly being dead at the hands of his brothers. Melisandre to the rescue!