The shoulders are too narrow. You can see very clearly where the shoulders end (since they're so built up) and then his deltoids extend a ways beyond there.
I'm going to go out on a limb and guess he's not a competitive bodybuilder so that could pretty easily be solved by a bit more (enough?) room in the shoulders.
That would, like you said, likely mean more cloth across the shoulder blades. It won't look as clean but I imagine it'll be more comfortable to move / use his arms.