I like the arms, the hands are good too. I dont know exactly what look you are going for with the head (im an anime artist and so therefor i only know a couple looks ) The thighs actualy dont bother me too much, i have seen that in such movies as disney''s lilo and stich, as well as other hot-box movies. None in games, but i dont see why it wouldent work. I do see some major problems in the way you define her "4-pack", hehe. I would also look at the breasts a little, you might want to refine them a bit, look at jdillons tutorial on breast placement and size at www.howtodrawmanga.com, it is really good and will help you out greatly.

that left arm looks like something I would draw, do work on it

There are two things that stand out to me. The widest part of a females body is the widest part of the hips. The widest part of the hips is right inline with the crotch. The skiniest part of the waist is a little above the navel. If the arms hang down straight the elbows should be pretty much inline with the skiniest part of the waist.

To learn about these and all other aspects of bodies, I suggest picking up a book on anatomy.