My suggestion is to try to sculpt or model in definition that should be in the mesh.  Like ribs, basic muscle shapes, etc.  Also to try sculpting on the face.  I notice some poles on there now that might be hard to sculpt because of how they respond to smoothing.  But it's hard for me to tell. Personally, I've found the act of actually trying to make morphs reveals limitations more than guessing based on theory.