I'm still having a hard time deciding between the various objective story domains. What is the objective story domain of a movie like The Wizard of Oz?
That's a good question. The Wizard of Oz is an odd bird because of the "It was all a dream" aspect of the story.
If you ignore the bookends at the beginning and the end except to see them as a setup for the OZ part of the story, then the Objective Story throughline seems to be a Situation. Conflict exists so long as Dorothy is in Oz. However, it's hard to leave out the beginning and end.
The objective characters are relatively easy to identify, and Dorothy is the Main Character. But who is the Impact Character? Is it her three companions? Is it the Wizard of Oz? Is it Glinda? Does she change or does she change them?
It really makes a difference where you define the beginning and end of this story. Dorothy seems to change and learn to appreciate her home ("There's no place like home."), but then what about Toto? She ran away to save him. Now that she's home, is she going to let him be destroyed? Most audiences don't think about that because the movie's over as soon as she's back. But if it is so important at the beginning of the story, why has it lost all importance by the end?
You see, The Wizard of Oz is more like a fairy tale than a grand argument story when taken all together. It's message seems to be stated, not argued.