well, I guess as in the movies and books you are just a spectator, you are tied to where the scene wants to take you, you are not free to explore, so in these cases the stairs don't need to have logic (besides in the movies the inside of the castle has no relation with the outside design), but in the video game you have the control of where to go, so I guess it was difficult to design magic stairs that move randomly without sense to places that go nowhere in such a small space limited by the fixed size of the tower. It is clear that they tried different models but in the end the situation forced them to choose this design.
