Iammatt's Rubinacci photography is so dominating as Rubinacci samples on the interwebs that one might fall prey to thinking that is how Rubinacci looks. But, it just might be a look peculiar to him.
I think you've hit the nail on the head. The softer the jacket, the more dependent it is on the shape of the body underneath. Matt (iam)'s look good becuse the cut and construction is a good match for him. I'd posit it's not for everyone.