"I don't think playing a villain is my greatest talent"

Sam Waterston is recommending that playing a bad guy is not his greatest skill. He is indicating that he has other talents that he values more than playing a bad guy. This might suggest that he is much better at playing a hero or a more intricate character. It could likewise imply that he has other skills beyond acting that he values more. He might be referring to his abilities as a director, manufacturer, or writer. It might likewise suggest that he values his abilities as a speaker or his capability to get in touch with individuals. Whatever the case, it is clear that Sam Waterston does not think playing a villain is his biggest talent.