DC has done a great job IMO...
With AB in the lineup this team is challenging for a playoff spot, without him they are a bottom 5 team, and that has nothing to do with Casey, it's just that he has little talent to work with aside from AB.
They are among the lead leaders in Opponents FGM, and FG%. They also have a respectable opponents PPG compared to last years.
That game against Utah should be enough to validate the type of defence DC has instituted. Anyone watch the final quarter and both OT's? Did you see that defence?
Give him a team to work with now, and the results will come.