Undoubtedly women have been pushed to the side in philosophy, and if and when I graduate with this damn PhD, I'll be hard pressed to tell future female philosophy students some of the experiences I've heard about. With that said, it is also incumbent upon us men to highlight those women that have had considerable impact in moral philosophy. 200 years is a long time, and certainly we have had women in the 20th century than should have made the list.
To be fair, Leiter has included many seminal works in analytic and Continental philosophy respectively.
I nominate several following women whose works should be on the list. Certainly, there will be disagreements, but part of the sensitivity to women in the profession revolves around interrogating the philosophical reasons as to why that exclusion happened. Therefore, while some of these thinkers might be labeled more directly feminist than others, I think it is hard to claim that feminism is, in principle, not a form of moral philosophy. Feminism is so steeped in both a criticism of the history of philosophy and overriding normative concerns in both the history and contemporary life it can never be non-ethical. I don't even think the claim could be argued personally.
Judith Butler (Say what you will. Butler has wholly embraced the controversial thesis that values are wholly a social construction with specific with attention to gender and bodies)
Simone De'Beauvoir (especially Simone. To suggest Sartre over her "Ethics of Ambiguity" is a crime of clarity and sophistication)
There will, of course, be others. I am not perfect and this is off the cuff. Feel free to suggest more.