Much has been made about the relationship between Celtics head coach Doc Rivers and point guard Rajon Rondo over the years. It’s becoming pretty apparent, however, that the coach-point guard relationship is only improving as the two spend more and more time together. In fact, the coach is downright impressed with the continued development of Rondo as one of the game’s elite point guards. Speaking on The Dan Patrick Show on Tuesday, Rivers, like Celtics president Danny Ainge, admitted that the Celtics explored the idea of trading Rondo last year for Chris Paul. That didn’t work out, of course, and Rivers seems more than fine with that.