The world a main character is in in the beginning of their story should sort of influence their choices.
Luke is a farmboy with aspirations of something greater. Him living in the center of a wide open salt flat helps reinforce this.
Mos Eisley is a sketchy town with weird people, because they’re looking for a sketchy character in that place. If Han Solo was any other sort of character Mos Eisley would NOT be a proper place to meet him.
We meet Lando as an administrator of a mining guild. This goes in complete contrast with his character as established by Han in an earlier scene, “Card player, gambler, scoundrel”. This sets up distrust in Lando from the moment you see him. Which is perfect - because he inevitably betrays the main characters. (It then flips back around, further developing his character and the audience changes their mind about him.)
We meet Obi-Wan in Episode I in a conference room. He isn’t given any personality or likable character traits until after the first action scene “The negotiations were short.” It’s okay to do this, but you should spend time with your characters. If Obi-Wan and Qui-Gon talked a little about the force and set up their characters, we would care a little when they pull out their lightsabers.
We meet Anakin, a good-hearted slaveboy in a similar environment to Mos Eisley. While the difference in his surroundings vs his character could have been an interesting aspect of the story, the script just doesn’t explore that. So him living in Mos Espa or even on Tatooine for that matter dosent influence his character.
Plus, in a trilogy about Anakin, he’s an awfully passive protagonist. He makes no decisions that affect anything (for the first two movies) and when he finally does make a decision it is completely out of character.
George probably thought up a list of locations before writing any of the scripts, and wrote the plot around those locations. That’s what he did for Episode III, at least.
