Watching it with the laptop patched into my HT in Pro Logic, and they sound fine to me!
I noticed Deems' voice seems to be slightly spread across the front channels, while Corey's is dead center. I attribute this to the differences in the way their voices were recorded and mixed.
I'm starting to see why the Taylor segments were trimmed in later versions, he practically gives away the Sorcerer's Apprentice plot in the "restored" portion!
It's funny how 35 years later, I remember a little kid in the theater yelling out "Bye Mickey!" after he shakes hands with Stokowski.