LogFAQs > #933116141

Greedo shooting first damaged one of the most important characters in the Orig Trig. Han just murdering Greedo to get away introduces him as a dangerous and desperate smuggler, a guy with skills who lives on the edge of the galaxy. It gives his character a place to develop into as he becomes sympathetic to the Rebellion and focuses on more than just saving himself all the time. It also establishes him as somebody not to be fucked with, and makes it seem like a plus for the Rebellion when he helps them, which it definitely ends up being.

When Lucas ruined the scene it makes Han look like a desperate loser who only survived some low level lackey like Greedo because of luck, and removes a lot of the impact of his character. It's a little thing, but when it comes to characterization, little things really matter. That Lucas didn't get that shows why Star Wars was contemptible garbage when he was in sole control.

The rest of the stuff was all added after Lucas made it clear that he was nothing but a ruinous force toward the whole franchise, and it being crap is to be expected.