GREAT updates, Nur!
The arm looks much better in these designs #12 #13 #14 #15. Notice the three parts of the arm - shoulder, middle bicep/tricep, and forearm. The top part (shoulder) is too much bigger than the middle. Notice that your bicep is very small now. Your first design had a more correctly shaped bicep but that arm was too plain.
See if you can make an arm more closely to the one at this URL:
http://www.oocities.org/gwilson67.geo/bicep.gifGREAT WORK!!!!