Aside from things like cleaning up matte lines, the ONLY SE change I could ever stand was opening up Cloud City in Empire. I always thought the hallways, rooms etc. looked a bit claustrophobic for a city the clouds, where spectacular views would be a must, and I loved seeing out those windows as everyone was running around, it really opened it up. It's the only thing I miss when watching the OUT.
That said, I agree with those who say the most likely scenario is they're planning on a straight up restoration of the OUT, which is what we all want. My biggest concern is that they won't do all the painstaking colour correction that Harmy did in trying to match the original theatrical releases. I just don't think that's going to be their priority...but hopefully I'm wrong about that. A lot of those choices are largely artistic, and their frame of reference might not be trying to match how the films originally looked.