I remember reading somewhere that Tolkien had given Gandalf four big confrontations with major villains, each one weaker than the previous and each time Gandalf wins a kind of victory. So The Balrog in a sense killed him but he came back, the confrontation with Saruman ended with Gandalf breaking his staff, The Witch-King turned away from him at the gates of Minas Tirith and Gandalf does not believe The Mouth of Sauron has Frodo captive and this is confirmed when the other squirms after being asked to produce him. Every time Gandalf reveals his inner strength or his superior intellect.
In the films the first of these two confrontations are much the same but the Witch King over comes Gandalf and breaks his staff and I noticed that after this Gandalf seems less sure of himself, he seems to despair in "The Last Debate" scene that he has sent Frodo to his death and it is Aragorn who comes up with positivism and a way to help Frodo, and when Gandalf is told by The Mouth that Frodo is a prisoner he obviously believes him, you can see it in his face, and once again it is Aragorn who rallies him (and everyone else) I wonder if this is to do with "Men" raising the standard of hope for when they take over the world and relying less on more magical beings. any thoughts. It's also odd that of these four confrontations only the first was in the theatrical edition of the film