Aside from adding C-3PO's extra line about the tractor beam, the 1985 mix is not really a remix so much as a remastering. It is basically identical to the 35mm stereo except with slightly clearer sound quality and a wider stereo image, probably achieved through digital processing.
The 1997 mix, while obviously far better than the 2004 version, does have its share of issues. High frequency noise is a problem--just listen to any of C-3PO's dialogue and you'll hear it. Whoa! This is present of previous mixes but nowhere near as strongly as that. The dynamic range is usually pretty good, but often not even close to the 70mm version, especially in the beginning of the film. The general EQ also gives it a somewhat tinny sound throughout.
Given that, it is understandable why they wanted to remix again for the dvd. Unfortunately, they screwed that up so badly that it would have been far better had they just not done anything to it at all. It is very telling that one of the 2004 version's biggest problems is that the EQ makes it blast out bass above all else (I'm not talking about the LFE channel) and kills the highs, taking the issue of the '97 version in exactly the opposite direction, but to a much greater extreme. The sound became so muffled and distorted it's barely recognisable.
Since it's the same guy doing the Bluray, and they never admitted to any problems, I doubt they'll do it from scratch again. It will be a further modification of the existing mix, rubbish with even more garbage piled on top of it. If they actually did fix anything at all I'd be extremely surprised.