Wasn't Superbit just a higher bit rate audio, much like what they have now on BD, not refering to the HD audio but the standard audio track on BD.
Actually, the Sony "Superbit" process was a little bit of the opposite of what you said in that reviewing the specs that came with the discs(I have three of them)by eliminating most if not all of the extra features they were able to use that space by "theoretically" upgrading the amount of space for the video by encoding at almost double the rate thus, improving the picture to its max capabilities for the DVD technology. The audio was left pretty much intact as before, with both DTS & DD 5.1 soundtracks.
