Re: One particular SPOILER from The Name of the Doctor
Good point about the Valeyard just having been mentioned in "The Name of the Doctor." It occurs to me that if Moffat put in all those lines about the darkness of what the Doctor becomes toward the end of his life, and told a story that focused our attention toward his future and his ultimate fate, that might support the idea that Hurt represents something from the Doctor's future, whether the Valeyard or something else. (And yes, the Doctor speaks of that incarnation in the past tense, but he's a time traveler. He spoke of his own eventual death and entombment in the past tense too.)
It's possible it's a future incarnation, but I doubt it's the Valeyard. I don't think they would hide the ball so shortly after explicitly referencing him.
When on Romulus, Do as the Romulans