I mostly disagree with Cameron here, even though two of my favorite female protagonists became decidedly more badass in the two sequels he directed. Wonder woman was excellent in this movie; you don't need to be ugly or an alcoholic to be a positive portrayal of a female protagonist.
Given that she was brilliant, strong, and had a strong moral compass that she stuck by even after being confronted with the reality of the world, I have to think his real criticism is simply that she was hot as hell. That last quality does not make her a poor protagonist, just as so many great male protagonists through the years have been crazy attractive as well.