Some of the coaches deserved to go. P.J. Carlisemo was a poor signing to begin with last season. At 2-21, the Oklahoma City Thunder are on track to record the worst season in NBA history, currently held by the 1972-73 Philadelphia 76ers at 9-73.
Thunder GM Sam Presti has some work to do. He traded away everything to go young and build around Kevin Durant and Jeff Green, but no matter how good any player is, they need a few (good) experienced players around them.
It's funny how some players rate themselves. Look at Shawn Marion and Raja Bell for instance. Both thrived in Phoenix under Mike D'Antoni. Marion tried to bluff Steve Kerr and Kerr sent him to Miami. Now, Marion still has exactly the same skill set he always has, but without Steve Nash and not playing under the Suns' offense, Marion isn't anywhere near the All-Star he was.