Jon never quite figured out who he was. He only knew he was the bastard child of Bed Stark. It just wouldn't be fair that he dies so abruptly, and guitar frankly, a shitty thing to do to watchers and readers alike. To just cut out an entire story, with all sorts of loose ends attached, it's just total crap. And for that reason, I don't believe Jon Snow's time is up just yet. Same thing with The Hound, and even that bastard Stannis.