Without a doubt, the best example of hindsight adapting so far. In books two and three, Margaery is more plot than character. The reader doesnt see very much of her. In A Feast For Crows, she starts playing a much bigger role, but even then shes rather passive. Benioff and Weiss saw a great opportunity here. After all, House Tyrell is extremely powerful, so the family should be comprised of shakers and schemers (like the Queen of Thorns). Margaery has her sights set on becoming Queen of the Realm, and she knows that wont be simply dropped in her lap. We see some very pragmatic cunning on her part in season two, most especially when shes trying to seduce Renly and when shes making deals with Littlefinger. Her part in season three is even more involved, especially in the way she maneuvers and manipulates Joffrey. Margaery has some major stuff coming, and this great character development will make those events even more impactful.