The show may very well be already spoiling the books.
Which questions will season 6 and/or book 6 answer?
Will we learn who the three heads of the dragon truly are?
Will any of the questions of parentage(Jon, Tyrion, Aegon, among others) be answered?
I think there's already a large hint in the lack of casting for the young boy Prince. Does this mean he doesn't matter to the end-game?