To me the hourglass shape too strong and too high, as opposed to stylistic. You've probably seen this already, but this Andrew Loomis example shows that perhaps the indent should be lower than it is. The hips look too wide for the shoulders - and especially on such a small waist. IMHO, anyway.
http://www.create-fantasy-art.com/images/AndrewLoomisBodyProportionsFemaleSmall.jpgAs far as the pelvis goes, it had me stumped on my old sprites as well when Atnas mentioned it. You can find a clearer example here, demonstrating how the legs don't really terminate at the crotch, but creep up around the sides on the hips, resulting in - especially at the size you're drawing - a bony ridge around the navel:
http://1.bp.blogspot.com/_-H-t-Wz1VNU/SZOlW51sIsI/AAAAAAAACQY/cLADH5GOTg4/s400/06AndrewLoomis_FigureDrawing_96.jpghttp://img339.imageshack.us/img339/3383/107nt5.jpgWhat do you mean by 'more detailing'? You already have plenty of shades - the difference in lighting and lines between frames seems like it could be more fluid. Any more (heck, as is with 8 frames at that size anyway) and you're risking burn out for the massive amount of work involved in any other animations.
I'm no expert, but hopefully some of that is on the right path and will help you find what you're looking for.