Hate to say it, but this is pretty much an automatic reshoot.
Some things to keep in mind on location:
- shooting wide open on almost any lens will produce a noticeably softer image than stopping down to the "sweet spot" which will vary by lens. f/5.6 is usually a pretty safe starting point for optimal sharpness.
- NEVER try the artsy tilt thing on a professional headshot. Unless the subject is in a rock band...and even then, think 3 times about it first.
- even a flimsy piece of foamcore used as a reflector off the subject's right shoulder out of frame would have made that shadow on his chin go bye bye. Hard shadows don't belong in these types of shots.
- as you already noted, the composition of placing the change in background right through the middle of his head wasn't a good idea. But you noticed that one yourself...after the fact. I'm confident you won't make that mistake again.
On the positive side, the exposure and color seem to be spot on. So you're definitely doing some things very well.
Hope that helps!