Robert Downey Jr as the Wizard of Oz?

I read an article in the Guardian website about the possibility of Robert Downey Jr playing the Wizard of Oz.

The proposed film would be a prequel to the classic 1939 film with Judy Garland, and is tipped to be called Oz the Great and Powerful.

It's fantastic to see Robert Downey Jr back and having so much success, with films like Iron Man (and the soon-to-be-released Iron Man 2 and 3!).

No doubt seeing him play a wizard (a well-known wizard at that) would be fantastic although it could be very risky to go near such a beloved classic - mixed feelings. Although I suppose it's similar to Johnny Depp's roles in both Charlie and the Chocolate Factory and Alice in Wonderland.