The first trilogy wasn't "all his". He only directed one of the movies.
Right, but he owned every aspect of Star Wars. It was his desision to hire kershner, he wrote the story. He gave his story to kershner and said this is my vision, make it a reality. He used he own money to finance. He stopped directing because he almost had a heart attack filming the first one. He had just finished directing and writing his last two films, Star Wars and American graffiti. Both films nominated for best picture and best director. He could have if he wished continued to direct but felt there was to much to oversee and hired Lawrence Kasdan to create the screenplay off his story treatments and kershner to direct.(who happened to be Lucas's teacher at USC.)
Kershner was an excellent choice by Lucas and really brought in a visual storytelling style that gave warmth and humanity to the characters. An example was when r2d2 is outside of yoda's hut. It was kershner's decision to have r2d2 stand up on his tippy toes and barley peer into the window while yoda's and Luke were talking.
Small moments like this brings in a child like quality to r2d2, it humanize a the robot and in turn the audience cares about the droid friend. There are many small choices through out the film that just bring the whole thing to life. Han saying "I know", instead of "I love you to" is another.
But all the story elements and structure you see on screen in empire is from George Lucas's mind. Didn't come from anyone else.
Story treatment of empire strikes back from Lucas hand written notes....
http://secrethistoryofstarwars.com/empiretreatment.html
Part of it here taken from Lucas hand written notes...
the Empire Strikes back.
story treatment by George Lucas.
11/28/77
Open on the bleak white planet of Hoth. Luke is riding across the windswept ice slopes on a large snow lizard (taun taun) He reins* up on the gy two legged creature when he spots something on the horizon; a strange ice formation, or meatorite hit. Luke talks into his walkie-talkie which is on his helmet. He lifts his snow goggles as he says "Han, ol buddy everythings OK here, but I saw a glint on the next ridge, and I want to check it out." Over the com link we hear Han say "OK but don't take too long kid, nite storms comming up." Luke says a few kind words to his lizzard, sinks his spurrs in, and the beast leaps forward. He rides over the ridge when suddenly, out of nowhere, a giant snow creature jumps up in front of him, causing the lizzard to rear back and throw Luke to the icy ground. the monster grabs the taun taun by its neck, killing the poor lizzard, then bashes Luke in the face. Unconscious, covered with blood the young warrior from tatooine is dragged across the snow by the horrible snow monster.
Han Solo rides his snow lizzard into a huge, beautiful but eerie ice cave and dismounts from his tauntaun. Its a big hanger for the rebel fleet, there is a lot of activity as troops and robots batter* down the space ships. Leia is in some kind of control area near the main hanger deck. Han walks passed workmen blasting corridor off the main hanger, and reinforcing things with metal gurters. He enters the control room and Leia asks where Luke is. Han tells her, that Luke wanted to look at an ice formation and would be delayed. He says " the whole planet is safe, and deserted, nothing out there, and the empire will never find us here." He's boasting about the whole thing. "now that things are set, I'm leaving." he Explains to the princess, which upsets her, and she becomes angry, icy as the cave. He says he must pay an old debt, or he will be hunted down.
R-2 + 3P0 are in the control room in same area, they comment on the environment, on weather the empire will find them, and R-2 is slightly concerned that Luke isnT back yet. Han leaves the control room and Leia stormes off after him. the robots comment on Han leaving.
the princess and the Pirate meet in one of the ice corridors outside the control room. Han Explains the reason he has to go, important. He has no choice. It's a mission that he must go off and complete at the end of the film. Han comes on to Leia, but she won't have much to do with it. She stays aloof of the whole situation and doesn't have time to fall in love. She rejects Han as a rogue, and puts him in his place, but she gets a sparkle in her eye, and is slightly attracted to Han.
In the ice monsters lare*, Luke is in trouble. He regains consciousness and uses the Force for escape. He's fumbling with the use of the force. it's not very strong with him, (visualized through para psyapsyie* aspects.) the ice monster is always vague, and mysterious. Luke fingers a talsman around his neck, and talks about Ben to himself. He feels he must go to the planet described on Ben's talsman. Luke finally shows up at the base and explains the monsters, and danger. the rebels argue about thier safety, some think they may be able to control them, as they have the taun tauns. they have a discussion about the danger of the Empire finding them if they move again. In the process of this argument Luke is taken to a medical area. he has been beaten and battered quite a bit by now.
In the recovery room Leia takes care of Luke. he is obviously in love with her, and he tries to Express this to her. Leia says she can't love him, job etc, but gives him a sentimental kiss. this tenderness is broken by the enterting of Han and the robots, also Chewie. Discussion about Han leaving and concern about the Empire, and the snow creature. Han and Leia exchange a few snappy one-liners; He putting her on, and she putting him down, Luke is generally confused by all of this. The robots make humoros comments about it all. Luke tells Leia he must also go on a personal mission.
Han is starting to leave. Chewebacca is busy loading the Falcon when there is an attack of the snow creatures in the ice cave. there is a gun battle and the monsters are destroyed. three monsters attack Han. We still don't get a clear look at the creatures. Chewie fights one of them, sometimes he's a little afraid of mechanical things, but not afraid of these creatures An explosion and the power goes out.
Vader - waiting at center of the Imperial stronghold. It is revealed he knows where the rebels are, and makes preperations to go after them.
the robots are concerned about the monsters. the people are concerned about the monsters. protective measures are taken, and a plan to drive the monsters out of the base. A controler gives a damage report, they have lost all power and will freeze if it is not restored soon.