@zolroyce: @egg: About the don't ever expect to see a woman get killed by a man in a movie: He totally kills her. Runs her through and stands over her as she bleeds out. (spoiler tagged for major spoilers)
I think the OP is seeing fire where he wants to see fire. The fact that the movie takes place in the time period that it does and there are two pretty kick ass women in this flick is cool. They actually made a female villain that wasn't just a sex toy with a bad attitude and a mean left hook. They actually make her and her blood lust something you could sympathize with. Lena Dunham returns as the Queen of Sparta and she plays a conflicted hero type. I felt like they had great roles, but I'm a white male so what do I know.
Edit: Also, I just want to say that because of something that happens in an earlier scene in the movie, I think his offer to spare her was totally legit (and a little selfish).