It was less about the studio meddling and a bit more about the people who were involved weren’t in awe of George. His, at the time, wife was the editor on the first movie and she made a lot of changes in the editing bay to improve what was a bit of a mess they say. And don’t discount the amount of rewrites done on the fly by the cast. Carrie was taking everyone scripts and punching them a lot and she went on to become one of best punch up writers in Hollywood. Even Harrison Ford, a notoriously shy and conflict avoidant guy, was improvising his lines because he knew that Han wouldn’t say “I love you, too” even facing being frozen in Carbonite.