George RR Martin has revealed that Sansa will have a controversial chapter and many people are jumping to conclusions. It seems to me that the majority of people on this forum believe that it has something to do with Sansa killing Petyr.
But what if it was different. What if this controversial chapter is Sansa killing Robin Arryn and finally becoming what Littlefinger wants her to be. No doubt she's already learning the Game, and personally she seems to be leaning toward the darth (sorry could't help) side.
So maybe the controversy is Sansa becoming Evil. I've always had a feeling that not all the Stark children could be good, honorable people. My guess is Sansa will become the new Cersei.