One thing to make sure about the Cloud City scenes is to NOT repeat/re-use cloud patterns (Even mirror/reversed ones) unless it's in the same scene seconds later which is rarely the case. In the SE shots of the the hallway with the people listening to Lando's intercom announcement the same buildings and clouds outside the windows were used in reverse (Flipped/mirrored) later when Leia and Lando are shooting at the troopers just before they escape on the falcon. A new matte of buildings and clouds should be created for one of them so the shots are not repeated. I hate reused mattes even in flipped/mirroed shots, they are always obvious to me.

On to the same subject of flipped shots, the Naboo celebration added to the end of ROTJ was flipped from EP1, they added all the crowds celebrating, but they could have at least changed the lighting and put all new cloud patterns in the sky. That would have helped a lot.