Doctor M said:

...and the final product isn't always representative of what is released in other countries. Jungle Book is the same era and uses xerography like Sword in the Stone. I don't see the U.S. release looking much better than SitS does.

As far as the Little Mermaid audio: The first LD release of LM has Dolby surround (2 channel prologic), which would be based on the ORIGINAL Dolby theatrical mix. IIRC, in theaters it was a sort of analog equivalent to DD 5.1. This disc is pan and scan.

The 1998 LD contains the 5.1 digitally remaster soundtrack from the 1997 release as well as a mono and Dolby surround track. I'm not sure if the latter two are downmixes of the '97 mix or from the '89 mix.

The first DVD is pretty much identical to the 1998 LD. It is non-animorphic letterboxed and contains the 5.1 digitally remastered track.

Imdb claims there was 70mm 6-track original release mix. I couldn't prove it, but it's possible.

I couldn't tell you if there is much difference between the '89 and '97 mix. It's most likely that they just reproduced the Dolby analog mix as a Digital mix because theaters were changing over.

This would be unlike the DEHT mixes where they assume you only have TV speakers and are half deaf.

With a little google-fu

Little Mermaid, The Spherical (Super 1.85:1) Nov 15 (USA) 6-Track Dolby Stereo Walt Disney

OAR blow-up. First spherically photographed Disney animated film to be blown-up to 70mm.