Oh yes, Guinness couldn’t stand most of the dialogue from the script he got despite enjoying the script quite a bit. Lucas is just pretty bad at fully grasping the way humans would naturally talk to each other in a normal context. He’s great at capturing and reproducing, and, well, writing that which speaks to the core of each one of us, I believe.

Also, Star Wars’ script was picked by the AFI as one of the best ever, while none of the other films’ were, not even TESB, so that has to say something about his writing. I believe American Graffiti was at least nominated as well.

And I don’t quite buy the people that say that Star Wars’ script is only like 30% Lucas.