You know what Luke wants right away: He wants off the farm and to be a fighter pilot. He wants to be an adventurer and a hero – specifically, and concretely, although the movie does a great job of cloaking it until the satisfying reveal, he wants to rescue the Princess and blow up the Death Star.

The motivation is right there, from the opening character scene of Leia and R2, which is then captured on hologram: Princess Leia (“She’s so beautiful!” – tangible motive 1 established) hands the target Death Star plans (“We’ve got to help her!” – tangible motive 2).

That massive two-punch arc precedes the protagonist, they are so critical to the form of the movie.

What’s so great about this arc, as slavish as it adheres to Campbell’s Hero’s Journey, is that the kid stays as a blissfully unaware of his driving focus basically until the denouement, but it is there all along.

So, Luke thinks he just wants off the farm and just wants to be a pilot, but the real driver (Princess/Death Star=Galactic Hero) is right there, even though it appears that Luke’s role in it is small at first.

He gets to Obi-Wan because he screws up and gets in trouble. He gets off the farm almost instantly because he unwittingly convinces his adopted dad to buy the beautiful Princess and Death Star plans bait. He’s “not such a bad pilot himself” who nevertheless relies on an old man’s judgement of crook to fly them places.

He’s a little short for a stormtrooper. He’s too ignorant of his target the Death Star that the beautiful Princess has to blast her way into more trouble, where the Target’s scrap garbage nearly drowns him automatically.

His obstacles throughout the plot, in other words, are almost ALL entirely generated by the avatars of his two big motivators: the Princess and the Death Star!

Why does he want to be a Jedi “like my father before me?” Because it moves him closer to getting the Princess and blowing up the Death Star.

In short, I totally agree that SW works because it is a moral story, but I disagree very much that the protagonist’s structure or motivation is in any way vague, inconsistently portrayed, or underdeveloped.

It is intricately and deftly developed. We just don’t make the connection until Luke does, at the same time that he does, when he finally realizes that he actually is the only one in the galaxy who has one single chance to achieve the dream he’s been chasing for the entire plot: to put away the pilot trappings and, with one subtle expression of the Force, save the Princess, destroy the Death Star and complete the heroic adventure.