Mat boxes remind you that this was done with blue screen. Crappy lightsaber colors and effects remind you that the characters are just using props. Grain, hair, and watermarks break your willing suspension of disbelief when watching the film. Clean those up, and no one would demand "Hey! I want my dirt fleck flaws back in my movie!"
Changing the storyline is unexceptable. Esspecially in scenes that didn't need any change. Han shot first, dammit.
Clean up the film, make the saber's more professional looking, and fucking keep Jabba out of A New Hope.