I like that Owen and Beru aren’t the evil step-parents of traditional fairy tales. Lucas wanted to do something like this in earlier drafts, having Owen smack Luke around, etc., but it works much better as it is in the film.
Owen’s just an ordinary Tatooine farmer, well-meaning but parochial, who gets killed because he accidentally stumbled on something the Empire wanted. It reinforces the evil of the Empire in a way dialogue never could.