I get it, but that roster is Deangelo Russell, Joe Harris, Caris Levert, Demarre Carroll, and Jarret Allen, with Dinwiddie, Crabbe, Ed Davis, and the Manimal off the bench. That isn't dogshit. Per the link you posted, their expected W-L was 41-41, and they went 42-40 to get the 6th seed in a shitty East. He was one game better than expected, whoopdeedamndoo. 42-40 this year would be the 11 seed in East.
I'm not saying he is a bad coach, he is certainly solid. But I don't see him as much different than Borrego who was also solid. I don't get why you fire a guy who has successfully rebuilt a bad team to two games over .500 in favor of a guy whose greatest success was also building a bad team to one game over .500 in a much worse conference. Absent a [Redacted]/Manning situation, you don't fire a coach unless you have a significant upgrade already teed up.