Coaching is kind of overrated in the NBA. Larry Brown went from back to back finals to a 60 loss season, Doc Rivers went from a 60 loss season to a title. They didn't suddenly get a lot better or worse, they got/lost players.
Right, I somewhat agree but if there's anything that they need to do aside from in-game decisions that are competent, they need to stress defense. In practice, you don't teach Steve Nash and Amare Stoudemire how to score the basketball together, that sh*t comes naturally. You will your team to get consecutive stops, thats what makes a difference.
You think Spolstra is teaching Wade and Lebron and Bosh how to score? Look how they play team defense, how they rotate, how they help, how they help off the help, that is where the NBA coach comes in.