It's just more excuse making, IMO.
A decent head coach would coax exponentially more productivity out of our current personnel. A decent head coach would have us playing far more effective offense, and better defense. Period.
Whether or not that would be enough to overcome Duke -- a legitimate national championship contender -- is irrelevant. If Tony Bennet were coaching our team, we'd have 16 wins, and wouldn't be blown out every time we play a team with a pulse.
People can point to the talent all they want, and talent is certainly important, but it is merely the symptom of the problem -- not the ACTUAL problem.