To the extent Calhoun thinks that his plan matters, my guess is that he wants KO to take over when he's done, and he wants KO to pick one of Hobbs and Lefty to be his "George Blaney." The other of Hobbs and Miller will be gone. Having too many guys on the bench who have won a ton more games than your head coach isn't a great plan either.
As for changing coaches now, you would think we were undefeated under Calhoun and fell apart when Blaney took the reigns. The truth is that this is the same disappointing team under Blaney that it was under Calhoun, and Blaney is coaching knowing that this is Calhoun's team and not tryint to remake everything how Blaney might have done it if it were his team. Blaney is not the head coach -- he is an interim coach. And there is a big difference.
When Calhoun retires, Blaney is not taking over. But until Calhoun retires, this is his team whether he's on the floor or not, and giving a different assitant coach a clipboard is merely scapegoating something that is not the problem. The problem (or the biggest one) is that the players are vastly underachieving their potential. The only short term fix is the players wanting to win more and doing whatever it takes to achieve that.
I still believe that is possible. However, it gets less and less likely every day.