You can argue "great" but most anyone would also agree he is a "very good or excellent" coach
Much like your avatar, you are wrong here, sir. Roy is not a guy who could take his'n and beat your'n. In order to win, he has to have superior talent. Otherwise, they have to rely on his "offense" to score. I defy you to watch his teams consistently run plays and have consistently decent/good results. It just doesn't happen.
Conversely, watch how many times the play breaks down and the guy who ends up with the ball just ends up making a play.
The "respect" he has is garnered from having been around for decades and having the right friends. Of course no coach is gonna say anything other than, "Shucks, ol' Roy's one of the best in the business." at this point.