Interesting. Very.
Yes, sadly it was dumbed down, I suppose partly because he chose to make if for children, however he did not have to make it for that audience.
I can’t help but wonder if Disney felt the audience would be lost on an otherwise styled movie. Maybe Disney himself missed the point.
However, to this day I marvel at the backgrounds in that movie, they are just wonderful. The painters did not dumb down the visual effects of that forest.
The only comparison I would make is to Forbidden Planet’s backgrounds.
Here's one:
An another, showing how it's used in the film: