Funny, I thought Grace and the female soldier pilot died like heroes. Why can't women be heroes? Why was it sexist for the pilot to go down in battle, honoring her principles by not having fired on the holy tree of souls? There's nothing sexist about her death and there's nothing sexist about women dying as soldiers. Neytiri was a fighter. She saved her husband at the very end. What's this "safe" little mate argument anyway?
They didn't die like heroes, they were punished for not fitting the roles appointed to female characters, ie. wife or mother. Also, it wasn't their principles they died for. It was Jake's.
Traditionally in film if women step outside of their pre-arranged roles, they are punished. See pretty much any literature on feminism and film criticism.
You know,
Braindeer, I teach American literature and cultural studies (meaning I'm not entirely uneducated on the matter) and while you're right that this is a motif that
can be tracked through film history (literature, too), it is one possible reading. Since you're alluding to feminist criticism, you should know that there is never only one possible (let alone a "right") reading. Feminists are notorious for having all kinds of critical discourses going on (not a bad thing per se), but in fact so all over the map that it is positively antithetical to feminist thought to imply that there is.
Your argument strikes me as an attempt to pseudo-scientifically justify your dislike of the film. And I now realize that is precisely what bugged me about your post, your undue invocation of the gender card, which, in my opinion, is uncalled for in this case. Attack Transformers for stereotypical representation of women. Or the horrible It's Complicated. Or many other films this year or any year. But Avatar? Sure, women are always marginalized or penalized. But that's our culture, Avatar didn't invent that. Instead, one should be thankful for small favors and celebrate the fact that at least, this one has prominent female characters - in positions of power, no less - brilliant scientist, clan leader/warrior, a soldier... and they're all good guys (gals

). Those who die die in fact for their own ideals, not Jake's: Grace gets killed trying to save the Na'vi from exploitation, which she has always tried to work against (long before Jake arrived), Trudy dies doing the same after having not only broken the MALE HERO out of prison and deciding not to take part in the slaughter not because of him, but her own conscience. There's lots of female agency in Avatar that not male-initiated or aimed at traditional female stereotypes - seeking the domestic life and husband or motherhood. Watch An Education (or Twilight, if you want to feel like banging your head on the furniture afterwards) for some of that.
As for your argument about Neytiri... it just goes to show that when arguing with feminists, you're often just wasting your time if they insist on regurgitating the old hat "female characters are always portrayed as such-and-such". That's Cultural Studies 101, not feminism. A modern feminist perspective might point these things out and then also see the other possible reading above. Except of course when you're pursuing a certain political agenda and you plan to abuse a movie for tired polemics in service of same agenda.
I'm grateful that I can enjoy a film such as it is, let myself be absorbed by it - and then also see it from a scientific perspective and shred its ideology to pieces. But doing that will never compromise my enjoyment. That's called dialectics. Try it!
EDIT: As for Cameron's misstep being making Neytiri "sexy", you're utterly misunderstanding not just the medium film, but our culture itself. Where in the world is "physically attractive" not being peddled as the ultimate ideal? Film, music, advertising... Anything commercial sells with sexiness, male or female. How is this unique to Avatar? How can this be a point of criticism here when this is so ubiquitous? You're making such basic and obvious points that methinks it's you who has only started her reading of (feminist) criticism.