Women in The Silmarillion

I read in some press release or other that the reason Arwen had to be updated for the upcoming movies is because Tolkien's portrayal of women in LOTR is "unenlightened" in general and anti-feminist in particular. Perhaps --

But The Silmarillion seems to me to be very enlightened in its portrayal of women. There are plenty of strong women characters - Melian, Idril, Elwing, Aredhel, Haleth, and - above all - Luthien.

With regard to the last, there's an exchange of dialogue in The Unfinished Tales (which I just finished reading) that struck me as incredibly cool. When the young Turin comes before Thingol and boasts of the accomplishments of his kinsman Beren, Melian corrects him: "Beren, and Luthien." Good one, Melian! (I really dig Melian.)

The story of Beren and Luthien is at the heart of Tolkien's whole mythology, and woman's part in it is co-equal to the man's in every way. I think that's why I like the story so much.

Anyway, I'd be interested in hearing other people's opinions on the subject. Are there covert elements of sexism in The Silmarillion that I missed? And/or why is the role of women like Luthien and Haleth so striking in The Silmarillion and so much less so in LOTR?

P.S. To Eruve and Etherealunicorn: thanks for forcing me to read The Unfinished Tales with your posts on Celeborn. Enjoyed the book greatly and have started to read it again!