I tend to find it pretty difficult to describe in concrete terms exactly what's wrong with the 2004 mix, because it's so impossibly screwed up and unrecognisable that I don't even know where to begin. It's like the sound effects are all muddled and mushed together somehow, and there's no breathing room to distinguish them from anything else. To me it sounds as though they utterly killed the high frequencies, probably as a way of overcompensating for tape hiss, and boosted the low end to an absurd level. If you play the original mix through an EQ with the bass all the way up and the treble all the way down, it starts to resemble the remix. (Note that I'm not talking about the really low bass found in an LFE channel, I mean the higher bass registers in the main channels.)
TServo is quite correct in calling it 'unfocused', because there's really no balance between the different elements. Listen to the hallway shootout in particular, and try to find the 'rhythm' of the laser battle. Guess what: it isn't there. In the original, the different types of laser sounds coming from the rebels and the stormtroopers have a sort of back and forth going on, reflecting the camera angle and the position of the characters onscreen. In a way you can hear the 'story' of what's happening from which sound effects are dominant at each particular moment. In the remix, the rhythm is gone and the 'story' of it is indistinguishable. Background tracks for characters firing their blasters from farther away are mixed at exactly the same level as those in the foreground (ie, far too loud), meaning that everything becomes jumbled and indistinguishable.
The shrunken dynamics and muffled EQ are particularly obvious in the explosion of the wall when the stormtroopers appear. When Vader enters the rebel ship, that awesome rumbling wind sound in the original is just completely gone.
During the flyby, numerous laser and explosion sounds were added that don't correspond to anything seen onscreen, again interrupting the rhythm, and the original sound effects are mistreated. Some of the lasers are actually out of synch, occurring over a second earlier than they should, and their corresponding visible blasts are silent. Other sounds, such as the impacts from the blockade runner scoring hits on the Star Destroyer, are simply missing altogether. The music isn't really at a bad level here, but it is often shrill and harsh and definitely does not integrate with the rest of the mix.
These kinds of problems recur throughout the movie, making the entire thing an unsalvageable waste, but the beginning suffers from the most extravagant screw-ups. Elsewhere, the music is often muted to a low level, but is selectively brought up and down in a very obvious way, often corresponding to changes in camera angle. I haven't heard the Bluray mix, but from looking at the waveform of the LFE channel and from comments others have made, I'd be prepared to bet that it's almost identical to the dvd except for a few tweaks. It really is a shame that the vast majority of the public can only hear Star Wars by means of this colossal sonic failure, and that most of them won't even know anything's wrong. It is analogous to the visual problems of the 2004 transfer: superficially it might seem great at first, but take a closer look and all the absurd flaws become painfully obvious. Sure, the mix is loud, and it's in 5.1 EX, so uneducated home theatre snobs will drool over it while turning their noses at the originals for being in an older format, but should we all eat crap just because a trillion flies can't be wrong?
Anyway—I'm finally going to have more time, so I can get back to work on the new 70mm track. I won't make an exact estimate on when it'll be finished, but I'll try to get through it as soon as I can. As I've said before, the improvements over the existing version are subtle, but worthwhile. I'm still considering the possibility of an alternate version, which would retain a few '93 additions and add some mono mix elements, and possibly a couple of minor surround effects from the '97 SE.