Chris Paul doesn't like him, and Griffin openly criticized him during the season. I remember one interview where he said that they have no consistent defensive schemes, and that it changed from game to game, and he was very frustrated with it. The Clippers are trying everything in their power to re-sign Paul, and giving him some say over the coaching staff is probably in the cards.
Their roster is very talented, beyond Paul and Griffin. Crawford lit people up on nights, and Bledsoe is one of the best back-up point guards in the league. Billups struggled with injuries much of the season, but was solid when he played, and Barnes could get super hot as well. They had the best bench in the league in terms of net efficiency. Compare them to the Nuggets roster - a team that won more games than they did, and why - because of their coach. Coaching does matter on this level, especially when you get into the playoffs, where Del Negro is 10-19 and has lost all four series he coached.
I'm sure the guy knows basketball and is super smart - you don't get to this level otherwise, but he may be better in a different position. His offensive sets, defensive schemes, and substitution patterns were BAD at many times during the season. I have been saying this for months now, so it is not just a reaction to them being ousted in the first round.
Just because you were a good player and played for the best doesn't mean you are a leader.
Cheers
