He said it on the podcast HAPPY SAD CONFUSED. He wanted Johnny Depp to star, which is...well, it's...you know. However! I wish this would have happened.
"Impossible is just a big word thrown around by small men who find it easier to live in the world they've been given than to explore the power they have to change it. Impossible is not a fact. It's an opinion. Impossible is not a declaration. It's a dare. Impossible is potential. Impossible is temporary. Impossible is nothing.”
~ Muhammad Ali
Are we clear on whether he meant the musical version, or a film of Voltaire's original novella? If the musical, then yes, it's horrible casting; if the novella, less so. Frankly, Gilliam is one of the few directors I think could do justice to the material in live action. Pity that he could probably never get it made.
I would love to see Candide as a movie. I think that the John Caird version actually plays really well in the theatre and of course the music is some of the best ever written. It would work well in a film adaptation, but then again, my favorite recording of the score is the 1989 version, so what do I know.
"Impossible is just a big word thrown around by small men who find it easier to live in the world they've been given than to explore the power they have to change it. Impossible is not a fact. It's an opinion. Impossible is not a declaration. It's a dare. Impossible is potential. Impossible is temporary. Impossible is nothing.”
~ Muhammad Ali
^ Well then, there's always the compromise... do it as an animated film. Have Gilliam do the concept art Python-style, and have the animators adhere to it. The Caird version would work wonderfully for an animated feature, especially with the narration.
As someone who manages to weave breath-taking strands of genius with those that are deeply flawed, this does seem to be a good combination of material and director.