The body's ill proportioned and the joint of head and neck is poorly done. You get this way too petite neck going up into the head, there's no flow from head into the neck and in order for the neck to fit in the head it's smaller than it should be, and then the arms are about 2/3 the thickness they ought to be.
I've got the new Female TT on order, see if Sarah's gear and head will fit on it and if it improved things, even the TT arms are too small, but at least maybe the rest will look nicer. I really don't understand the basis for proportions on the female bodies, I just can't imagine what real female body ever gave them the idea, they don't look like any female body, not even anorexic models look like them.