If GRRM had kept a decent pace in getting the books finished I would be more inclined to believe that all the things we think are going to happen, have been hinted at, foretold in prophecy, etc, would in fact happen. But the vast amounts of time between that has transpired since ASOS was published to where we are at now had provided so much opportunity for everyone and their grandmother to openly speculate and theorize how each character arc will finish and ultimately how it will all end.
R + L = J
John Snow will be reborn
Arya will get revenge
The dragons will defeat the Others
John is AA
Dany will sit the Iron Thorn
Jamie will kill Cercei
etc, etc, on and on
And not that I think that any of these are out of left field predictions, it just that so much time has passed and so much speculation has been made, that I can almost see Martin rebelling against popular prognostications by taking some arcs to completely different endings. I think that ultimately the story will end as he has always envisioned it to, but how we get there could end up being wildly different than most think.
And really, he's old, rich, and seems to be short on f's to give. He may get some satisfaction out of permanently breaking the internet.
