One thing I have noticed in the DVD is that I have played Under the Sea on my VHS, and have noticed a change in Ariel's tail color. The color for Ariel's tail was specially mixed at Disney Animation (it's officially named after her). It's a specific blend of blue and green. I noticed in the DVD her tail was predomently green in the scene, whereas the VHS was bluer. Now I know there's a difference in color rendition between VHS and DVD, but I don't think it would change the look that much. I know that all art since then has it basically as green, and it did fluxuate between scenes a bit. I doubt given that the VHS was from when the film was new that it's a product of faded colors. So I'm guessing they color corrected it to be more green in scenes where it wasn't.
I'll compare it to the rip of the old DVD I have.
I also noticed listening to the remix in stereo that they definitely boosted the vocals over the music. The VHS is more balanced in this respect. THough I figure this is partially downmixing. You just can't beat VHS for stereo. ^_^