I know this is late, but it's taken some time to assemble my thoughts on this subject.
Last week, I talked about using the land of Oz, or some section thereof as a sandbox/pinball setting and creating things for characters to bounce off of. This week, I want to go to the heart of Oz, the Emerald City.
There are actually two levels to an Emerald City campaign: The Palace, and the City itself. Most familiar to Oz fans is the Palace, containing Ozma, Dorothy and all of their friends. It's where many stories start, end, or simply change.
The challenge of the Palace is that everyone gets along. A story can't really happen unless there's a conflict to resolve. Now, your characters can provide that conflict, trying to push their agenda and watching how their favorite Oz characters react to it. But if they just want to bounce off of the established cast, you should put more effort into strengthening the differences that the characters have.
While I tend to point to the Emerald City as the point where my playtest campaign fell flat, there were a couple of things that went well. Specifically, Bungle the Glass Cat and Jellia Jamb. The reason being that both of these characters had agendas. Jellia likes playing jokes on people and Bungle wants to be admired.
Coming up with conflicting agendas for the different characters doesn't mean that they have to become enemies or even stop liking each other. Take The Wogglebug and the Scarecrow, for example. Both of them are smart people, but go about it rather differently. The Scarecrow was created knowing nothing, and is eager to learn new things. The Wogglebug studied in the classroom of Professor Nowitall and is eager to show off what he knows. So the Scarecrow's agenda of "learn new things" can interact with Woigglebug's agenda "Show off what you know" in a number of ways, including a few that can create a story-worthy conflict.
Next week, I will stat some Ozzy thing from the books (If there's something you would like to see, feel free to ask for it) and the week after, I'll try to continue with a look at the mean (not really) streets of the Emerald City.