I think it's almost fair to say that Star Wars was great despite Lucas. Remember, he only directed and wrote the script for the original Star Wars, and that was when he was under the tightest control from producers etc. He basically just produced and wrote story outlines for the others.
It seems to me quite common in film-making that when someone gets the opportunity to do exactly what they want, with complete creative control, unlimited funds and no editorial oversight, then about nine times out of ten they will deliver some ridiculous fucking garbage. I'm not sure why this is: part of it I'm sure has to do with the fact that some people need to have their ideas picked over and have the stupid ideas weeded out (something that hasn't happened to Lucas for decades). Part of it might have to do with intricacies of the film-making process: it's an artform like no other in the sense of just how many people are involved and how many of them have a crucial creative role. Actors, editors, special effects teams, sound designers, costume, props and makeup, even camera operators and lighting techs are all creative people. If the director is just dictating on pure ego and has to have everything just their way, then it stifles the creativity of these people and they're more likely to just phone it in. Furthermore, ramping up the pressure and forcing people to improvise often creates some of the most iconic moments in film.
