Doctor M said:

I disagree. Many of the xerography animated films end up with bits cut off that don't look like they should have been when theatrically matted.

That could be just another example of Disney being slap dash in their home video releases, or the animators figured they had the whole page and used it.

FYI, the HDTV version floating around is less compressed looking than the iTunes version.

I think many of the versions released at 4:3 tend to crop the sides quite a bit. This would mean when matting to widescreen it would be over-cropped. This would carry over to their bluray releases if they didn't create a new master (and they certainly didn't for Sword in the Stone). One solution for us would be to just matte at a taller widescreen ratio (like 1:66.1).