I've only sampled the Blu-ray once and was so horrified at what they had done to the score that I never scrutinized the picture overmuch.

I agree that all of the characters other than Conan are thinly outlined. I think the film is a product of its time, and movies of the fantasy genre weren't really known for their characterizations. I think Milius would defend the idea that the film is told from Conan's perspective, but I think it would have bolstered Conan's relationships had there been more substance to them (certainly the emotion of the moment when Conan leaves Valeria is conveyed primarily through the music as opposed to the text).

I think this is partly what Milius was trying to accomplish in the director's cut with the additional scene between Conan and Subotai before the Battle of the Mounds, but while the content of that scene is interesting, it does come across (to me, at least) to be somewhat out of character for both to be so reflective to one another.