This isn't much of an edit because I think its pretty good already.
Agree with legs though, changed them a bit. The middle demonstrates her figure a little more than colours do. I think the legs were too thin. Made them a bit thicker around thighs, tried to get a sense of the calves/knees also. Made them longer in general, which required the shorts to come up a bit. Made the shirt less draping and long to keep the midriff showing, which I assume is a style you want to keep.
The only other real problem was the contrast and the saturation. Tried to make them less of a smooth ramp (see Hue Shifting). I left the colours in there as a comparison so you can have a look.
Edit: Oh, and I added a mouth, I think the piece can handle it but that's your choice. Also I think flat black and flat white are a little overbearing. Experimented a little by removing all the greys as well, but I think grey pants would be fine. Even near black and near white would be cool but I thought I'd compare it to this.