I have listened to all 3 commentaries, and I have to say nothing new comes out about the changes. The ESB is the only good commentary cause you hear Kershners take on the movie, and there is no prequel spin, or this is the way I envisoned it. Kershner is pretty honest and straightforward, and does a go indepth on alot of subjects, especially the cave sequence. Carrie Fisher adds some funny moments when Harrison Ford talks to her after Luke tells her he is her sister, and her and Han Solo have a tender moment, she says, "Ugh, I liked it better when we were arguing with each other in ESB!"
I used to love Lucas interviews pre-SE, because he was much more honest then. He actually was very insightful when he'd talk, and it was always interesting on his take on the OT movies. But now, he has to give the spin that the story was always about Anakin, or there were never 9 episodes, or Darth Vader is just this pathetic #2 guy, or I had to wait for the technology is why I never did the PT back in the 80's. It is all a big lie now, and sadly, I don't really care what he says, or I just think he is spinning his views so everyone sees the saga 1-6 now. But check out his interviews pre-97 interviews, they were always very interesting, and to me I think he was alot more humbler back then too.