Motives are difficult to discern. It's a complex film. There is a lot of subtext and a lot of stuff going on under the surface. For example, Lady Eboshi has no qualms about potentially ruining the balance of nature. At the same time, she gives hope and opportunity to outcasts like prostitutes and lepers by recruiting them to work in her village.
Flawed characters are always more interesting than the aesthetically perfect ones.
That's what makes it interesting as an actor. While Princess Mononoke has received a major push, Gaiman wonders if American audiences are ready for an adult cartoon. This is something that has been a frustration for me for 12 years, working initially in comics and still loving to do stuff with illustrations. While the fate of Princess Mononoke is uncertain with the U.S. box office, Gaiman recalls the one person who matters most gave it his blessing. He gave me a hug and told me how pleased he was he hadn't listened to the people who told him to insist it was released in subtitled version.