Sirius Black: Brilliant, Snape. Once again you've put your keen and penetrating mind to the task and as usual come to the wrong conclusion.
It was a deliberate directorial decision to change the geography of Hogwarts, but it still grates with continuity. Most of the Buckbeak scenes happen around Hagrid's hut, which is down all those steps and near the forest. However in the Philosopher's Stone, Hagrid's hut is about 5 seconds walk from one of the main entrances of the school, nowhere near a load of steps and huge hill. Also, the Whomping Willow (which itself differs greatly) is on the grounds of the castle, as you see it on flat land when Harry and Ron land the flying car in the Chamber of Secrets, however in this one it is right away from the school next to quite rocky land.
In order to acquaint himself with his three lead actors, director Alfonso Cuaron had each of them write an essay about their characters, from a first-person point of view. Emma Watson, in true Hermione fashion, went a little overboard and wrote an 16-page essay, Daniel Radcliffe wrote a simple one page paper, and Rupert Grint never even turned his in, as he said that is what Ron would have done.