I will say that Jon Snow not being in the novels kind of takes away most of the remaining relevance and importance of the North to the reader.
The North is where the whole thing is heading though. Daenarys, the dragons, Jon(if he survives), Stannis, Grey Worm, Brienne, Arya, Tyrion, Jaime, Sansa, Davos, will all end up there. Quite a few are already there.
I'm just not sure if GRRM will kill them off eventually or what.
The fat fuck is likely to die off himself before he gets around to finishing the story. He's even slower than Robert Jordan when it comes to getting stuff out. There's at least
4 books left in it, and going at his current rate, that could take 20 years to do. He's a morbidly obese 66 year old, so I won't be surprised when the news comes out of his dying of a massive heart attack. I just hope Brandon Sanderson is willing to take up the reins like he did with the Wheel of Time