The juxtaposition of 3D with traditional 20th century set building was very interesting. The landscape shots had a certain Truman Show-esque appearance, but only subtly so. I think it takes a certain video geekitude to study the 3D depth choices made in post.

3D often has a feel like a diorama made of cutouts. Everything is still flat, but at different planes of depth. It's an easy out that looks a little cheesy. They did a pretty good job of avoiding that. But the backdrops are treated as backdrops from depth perspective. The sets were so big, that if one doesn't focus on the backdrop one might not notice how wall-like it looks. But as soon as one tries to sort out where it stacks up the 3D depth department (aka z-axis), it's wall.

They could have created artificial depth in the backdrops. This is entirely feasible with current technology. They could have given the scenes the expansiveness of modern CGI/bluescreen production. But *that* would have been cheesy. In this case, maintaining the "diorama-like" back drop is truer to the original film. Oz is expansive, yet closed in.

(I think they may have done some of that "cheesy" backdrop depth manipulation in the hall of Oz, to create greater depth to the hall. That's one of may favorite shots of the whole film, and it looked great. So rules are for chumps.)