That's what you do in football. Someone proves they are good at a certain job, they get promoted. Bronco thought highly of him. Half of CB thought he was Bronco's future replacement. It's not anyone's fault that Doman wasn't good as an OC but Doman's.

Nothing wrong with letting go of Doman. I wouldn't have minded if he stayed on as QB coach, but Beck has done a fine job to this point. Plus, there were questions about Doman as a QB coach by the time his stint as OC was over.