maybe you're having trouble with the arms because his arms aren't really doing anything. So, maybe think of something for him to hold or have him rest his hands on something in front of him? Or behind his back? something along these lines only not so lamely painted?
get him out of the coner or crop it it there are alot of unused opportunities. some sort of action with the pose , some suttle or a sort of gesture to suggest movement. but over all nice. very creative character.