although i agree with you on the gwyneth and julia aspect, i don't think that part was written for a white actress to play.
the directors initially didn't want to give halle the part because they thought that she was too attractive and would take away from leticia's character.
you're right in saying that she was willing to do the scene that way, but i believe any actress given the part would have to have played it that way because that's how it was written. the graphicness totally fits in the storyline because i believe it had been, at the most, eleven years since she had been made to "feel good." so couple that with the tragic events that had occurred in leticia's life all at once w/ the drunkeness and you've got yourself a racy sex scene.
souls walking in unison along the Paths To Perfection...change your vibration and you will find a key to unlock all the Heavenly Glory.