There has been exactly one major POV character who was killed off and stayed dead. Ned. Every other major death was to someone who wasn't even worthy(in Martin's mind) of being a multiple chapter POV character.
Killing Ned advanced the entire plot. Without that event, we likely have some peaceful resolution and this is a 2 book series that is quite boring.
Killing Jon accomplishes nothing. There is nowhere for the plot to advance to with his death, if he indeed stays dead. Nothing on the wall changes. Nothing in the North changes. Nothing with the Others changes. They have all the same problems, just a new leader to deal with them. A new leader that not one reader will give a #### about.
I don't see how you can say this without having read book 6. It's presumptuous.
Didn't you say you were 95% certain he's dead?
I think it's nuts to say that if Jon dies, nothing on the Wall changes. Things change drastically with Jon dead, who was the only forward-thinking man dressed in black up there. There would be a complete reversal on the NW's position regarding wildings, it'd probably mean fighting, which would weaken the defense of the wall even further.
If nothing else, Jon's death draws a parallel with the rest of the realm. The Seven Kingdoms are throwing their strength at each other, all bickering over who sits on the Iron Throne. Meanwhile a threat that has the capacity to wipe everyone and everything out is knocking on the door, but they're too blind and caught up in their own petty affairs to care. Similarly, Thorne and his crew, and presumably whoever comes into power in the event Jon is dead, will hold on to old grudges, even though they actually
know that the cold winds are rising.
In that regard, Jon's death is very significant. That has a lot more weight to it than the theory of "Jon dies so he can technically be released of his NW vows." That would actually be some really crappy writing IMO. Characters should have to make tough decisions, and pay the consequences of those decisions. "Killing" Jon so that he gets out of his vows based on the fine print would be super cheesy in my opinion.
And again, if Jon leaves the NW, where exactly is he going? Someone in the TV thread (at least I hope it was the TV thread) said he'd be revived so that he could go become the Lord of Winterfell. How the hell is that going to happen with Stannis out of the picture? What else is Jon supposed to accomplish exactly?
Again, not saying he's 100% dead, but to say that his death would be pointless is way off base IMO.