Spielberg has wanted to do a musical since the late 1980's when it was intended for HOOK to be one. Ever since I saw WICKED back in 2003, a film adaptation, at least in my mind, is directed by Spielberg.
"The Spectacle has, indeed, an emotional attraction of its own, but, of all the parts, it is the least artistic, and connected least with the art of poetry. For the power of Tragedy, we may be sure, is felt even apart from representation and actors. Besides, the production of spectacular effects depends more on the art of the stage machinist than on that of the poet."
--Aristotle