I don't think Cal was an awful coach in terms of preparation. I think he was an awful coach in terms of in-game adjustments. He could do some at half-time but otherwise even the plays he might choose to call seemed poor decisions more often than not.
What Cal had was a reputation for top tier recruiting and putting kids into the league. That worked out great for many who passed through our program. That also encouraged others with great high school talent to select him as the coach. Of course, mainly this didn't little for the program achieving because of the favoritism and again poor in-game coaching. Any debate on "favoritism" ends with the knowledge that we just had two possibly top 5 or at least 10 draft pics and the player that is not even NBA ready started over both of them?
The actual game of basketball passed up Cal's skillset years ago.
But where I argue Cal always excelled was the business of basketball. He could recruit, sell a program (himself) to both the media and recruits, and hire guys who did know basketball to fill in the gaps. People who stick by him are generally fiercely loyal and it seems to go both ways.
But his ego is his ultimate downfall. He burns bridges when mad. Honestly if he didn't have so much of that he'd probably have excelled in that ambassador to UK basketball role and we'd have been better for it. But that would have had him taking a backseat to the actual coach and that's never gonna happen.