Mazz came in and Boston became the best offense in the sport and he maintained a top 5 defense. Under Ime they were 7th in offensive net rating (2nd defensive). That Ime year, the expected W/L was 59-23, yet they were 51-31. Mazz's 1st year with a much worse assistant staff, they were 2nd in offensive earing and 3rd for defense. Their expected W/L and the actual record were identical at 57-25. Mazz's 2nd year, they win the title. Either 1st offense and 3rd defense. Expected W/L was 66-16 vs. actual of 64-18. Last year, 2nd and 5th, 62-20 vs 61-21. This year, without Tatum, 2nd and 4th, 59 expected, 56 actuall. Without Tatum, without Jrue, without Al, without Kornet.
Mazz is an excellent coach at getting the best out of a team. He has consistently had a top flight offense and defense. His systems work. The team over achieves while consistently having a ton of roster turnover and injuries. Is he the best coach at drawing up a play on the fly, no, but his system works when the players execute. And the players execute the vast majority of the time.