I think the lack of response is it just lacks interest. Without having an emotional attachment to the subject it's just a profile with blown out whites on his shirt.
I'm quite new to this photo stuff so I can only offer what would interest me more as a viewer. Others with more talent might be able to help you more on the lighting and such.
To make it more interesting for me I would....try to capture a bit more personality by not having it so "this is the left side mugshot". More focus on the eye area might help as well.