spoiler (click to show/hide)
IE what if Jon rejects his role and goes rogue, or Dany truly goes mad, etc. He also says the Others aren't monolithic evil. We'll see.
The troubling thing is that he still hasn't fully gotten to the events that would have originally been the second book of the trilogy, ADWD. He originally planned for Game Of Thrones to end with the Red Wedding, and ADWD to largely be about Dany invading Westeros. The third book (The Winds of Winter) would be about the Others, mainly. I understand the five year gap fucked him up, and later the Meereenese Knot...but he has solved both. Yet TWOW might take nearly as long to come out as ADWD, and Dany still isn't in Westeros. Honestly I don't even see how she can get to Westeros in TWOW unless she leaves everyone behind and flies solo.
Like many fantasy writers he seems obsessed with world building and is unable to stop, and doesn't care what his editor thinks. The series is at a point where he's pretty much out of room for more world building, assuming he wants to finish in two books. He's said we'll see the far north in TWOW, which means we'll get Others world building (not that I'm complaining about that); someone journeying north or Bran getting an exposition dump, perhaps. TWOW has to pretty much be paced like the end of ASOS to get where he needs to get. So...the three battles (Meereen, Winterfell, Storm's End), Aegon crowned, Jon stuff resolved, etc. But the monkey wrench is Martin saying Dany will fuck around with the Dothraki for awhile...sigh. Just burn the khal and go home.