These accounts about Marcia are deserved but downplay the contributions of Paul Hirsch and Richard Chew. The three of them absolutely saved Star Wars in the editing room.

The lack of Lawrence Kasdan is the reason that every piece of dialogue in the prequels is incredibly awkward (but apparently extremely meme-able).

An accounting of changes made in the edit of Star Wars: https://youtu.be/GFMyMxMYDNk

It's a lot of things. Prequels are hard to begin with, and Lucas wasn't interested in shooting dialog