He never spills that kind of stuff on his blog because he thinks about what he is writing. In some interviews though he has let a few things slip, maybe intentionally and maybe by accident. He has said the stuff about knowing the ending several times, usually in reference to the show and how he has discussed it with D&D in case something were to happen to him. He also has spoken about it with stuff like, "It's kind of like you are taking a journey. You know you are going from New York to LA but you don't know if you might stop off in Chicago on the way or maybe get a flat tire. Sometimes you also get an idea of how you wanted to go one route as well and then you see a better way of getting there." That's why the Knot was such an issue, he had written himself in a corner and couldn't figure out how to bring the storyline back in, he just kept expanding it. I think Quentin was a victim of the "Knot", just one too many storylines.
He has said there will be no more new POV characters. My guess is there may be a couple but only to wrap up some storylines, esp in the Prologue/Epilogue where he kills someone off.
I think Jaime or Cersei or both get killed next book. Cersei's demise already has a prophecy. Personally I think Jaime finds a way to be her champion or to better yet fight UnGregor as the King's champion, that feels very Martinesque. In fact I think most of the Houses lose at least one POV. The real question is if he throws in one of the key Non POV characters to suddenly have a POV and reveal a ton of stuff such as Littlefinger, Varys, Howland Reed, Bloodraven, Euron, Rickon/Osha, or Stannis (whom I think is doomed).
Of course a Hodor chapter would be awesomeness.
