The new version technically wouldn't be a remake, because there were a lot of elements left out of the musical version from the book. The book is actually really dark and violent, which would not be okay in a film in 1939.
I think the book should be better adapted now. The last one we had was the Tin Man, which was very MEH and the only real good thing about it was Zooey Deschanel.
I think it should still take place in the same time that the book is set in, no modern s***.
I used to have a book illustrated by the Hildebrants, and the images in the book were gorgeous. I'd love to see the movie based on those designs.