Problem: There is nothing to improve. Fantasy creatures do not need "joints" on their wings because they are fantasy creatures. And medieval and classical depictions of dragons where not always depicted with jointed wings. My drawing is based on classical depictions (aka the original and historical dragons).
There is a difference between criticism and lying and telling people what to draw. Your description of a "dragon" is not only very limited to your own limited ideas but goes against classical ideas about dragons.