As we'd initially written, "The Whole Nine Yards" writer Mitchell Kapner wrote the script for the project, based on parts of a number of L. Frank Baum books. (It was called "Brick" back when it was first presented to Disney, but is now being talked about around town as "The Great Powerful.") The wizard, who in the Baum books was a charlatan in Kansas before arriving in Oz, is a more dark and complex character in the Roth/Kapner version than the desperate and doddering wizard of the MGM musical (played by Frank Morgan) would suggest, which in turn makes it seem like it would be perfect for Downey (and few others).
It's interesting that this is the prequel line that would become a movie first, considering that the more popular prequel that most of us are aware of was the story line on the Wicked Witch of the West as told from the musical "Wicked". It is also fascinating that Disney is doing this considering that they are already rumors about Tim Burton possibly doing a story on Mileficent, which I would think will also be a prequel before she became so bad in Sleeping Beauty. Is this a mere coincidence, or is there a pattern here? :)