I chose average, but I think he's a notch above that. I just did a quick list of NBA coaches and labeled then 1-5 and he comes up right in the middle of that group. So as far as NBA coaches go he's average. He probably could sniff the top 10, but he's not better than the following coaches
Popovich
Kerr
Stevens
Spolestra
Carlisle
Budenholzer
Stotts
Snyder
He's probably in the Malone, Snyder, Clifford, Fizzdale, Walton, Thibs, Casey, Atkinson group.