The one hint that Jon has a greater destiny that is not likely to change regardless of his "life status" was the potential for him to be a true Targaryen heir, and the revelation of his true lineage as not being a bastard-born son of Ned Stark. Littlefinger was starting to imply to Sansa that there was something going on back then that was not commonly known.The thing I don't get about people assuming Melisandre is going to resurrect him is why would she? Yeah, she was interested in him for a bit, but she had already counted her losses. And as others have pointed out, if she did, he wouldn't be quite the same person which would kind of defeat the point; especially since he's clearly destined to lead the Wildlings who are extremely superstitious and wouldn't take kindly to following a shell of a man resurrected by a witch's magic.
Whereas if he's pretty much resurrected on his own, and in doing so also fulfills everything the prophecy about the Azor Ahai without a third-party being involved, that would go a long way to winning them over right there on the spot.
On second thought, I would now actually agree with you that Mel might not have a hand in his resurrection. She may try, and find that she fails and thinks he cannot be brought back to life.
IN FACT, I would now even go so far as possibly thinking that, due to Jon's true nature, what would happen if the Night Watch try to burn the body, in keeping with the standard of preventing the potential creation of a new Walker? What if attempted immolation is what actually resurrects Jon? In the same way that Danny was impervious to fire, perhaps it has healing powers to those with dragon's blood. This could lead to a relatively "intact" resurrection, rather than using the imperfect "R'llhor" method.