First of all: Holy crap, you've improved leaps and bounds since I last came here.
You've done an amazing job foreshortening the legs and establishing volumes in the woman, particularly in the torso and legs. I feel like I could go over there and pinch her, and it would feel real.
I think that the leg on our left looks strange because the knee does not look like that when it is bent-- it is much, much rounder, smoother. Here are some pictures to show you what I mean:
(Sorry, I couldn't find very many photos! I hope these work.)
http://www.dmoma.org/lobby/collection/w_logan_fry/gina/images/degas_woman_kneeling.jpeghttp://www.shoeboxclassics.com/images/framed/homage_ltd.jpghttp://images.jupiterimages.com/common/detail/33/39/23183933.jpgAlso, on the hip connected to her other leg, I think that it would look better if you got rid of the line on her butt showing that the leg fades into the hip, and instead showed that line through your shading.
Secondly, something seems a little odd in the armpit area. I think that the rib area underneath the arm on our right should be less pronounced, and the arm on our right should start lower and thicker. The line from the breast should move smoothly into the armpit, but right now it ends at an odd angle in the ribs.
As for the pose itself... I can tell that you're going for the same kind of sexy vibe that is present in all your works, and it shows through in this piece. However, not having hands at the moment sort of kills it. Now, I know that this is a WIP, and that you simply have not drawn the hands yet. I cannot say whether or not you have anything planned for them. But hands are one of the most expressive parts of the human body, and so you should always be thinking about how their positioning relates to the mood you want to convey.
What are you planning for the hands? I can see very clearly that they are behind the head. From where they are, I'm guessing that they are going to me holding up / ruffling her hair-- which would work very well with this.
I'm afraid I can't be of much help with her feet. From what I can see, I think that they may need to be a little bit bigger. With her toes, remember to vary their lengths along the natural curve of the foot, and to have them curl a bit-- in that position, the toes would curl in order to grip the ground better.
I hope that helped, and sorry for not peeking in here sooner!