I think you hit it, offensive coordinators look at 1000 feet in the area looking down to the play , emphasize schemes and see them develop. The offensive position guys are the hands on player to player interaction.

you rarely see a defensive coordinator in the booth. They are the hyping/coaching up players. Defensive schemes are crafted, but at the end its the play of the defensive position. (I remember Bud getting so hyped to the guys).