There is just one piece of audio that I desperatly wish they would fix (but it might be impossible) is Luke's line of "Aww, it just isn't fair. Biggs is right, I'm never gonna get out of here!"
That line sounds like they had a windsock or something on the Boom Mic. All the other dialogue is fine, but line has always bothered me. Hell, if the sound has degrated so badly, why don't they just have Mark Hamill come in and do the line again. Luke's back is turned when he says it anyway, so it wouldn't be that hard.