Speaking generally of coaching vs. players (not as it specifically relates to HD/UNC), I think there are certain things you look at and can judge whether it’s on the coach or the players. For example, on offense, are the right players getting good looks but failing to execute? If that’s the case, it seems that the coach is likely doing a good job but that the players are coming up short. If, on the other hand, the right guys are failing to get good looks, and that occurs on a fairly consistent basis, it’s likely more on the coaching.
As for defense, poor defense on a fairly consistent basis is generally the sign of one of two things, poor coaching or inferior talent. Obviously talented players can be lazy on defense, but if that’s a consistent problem, the coach bears some responsibility there.