What’s neat about the whole series is that all the characters are more than ‘one-note’ characters and all have their moments of stupidity and redemption, obsession and selflessness.

ya, the characters did change. Now Susan seems back to her senses and is saving people.
LoA

Well, I guess nobody is all bad. A note of redemption for Susan being a hero and staying with her love. THX is right there is a great depth to these characters.