Now I'm confused..
My point is that a HC calling plays from the sideline isn't any different from a OC doing it because most OCs call plays from the sidelines. If most or all OCs have someone relaying info or pictures from the press box than I don't see why that would be different than if the HC is the one calling the plays as apposed to the OC.
Most Coordinators are in the press box not on the sidelines. The TV folks show shots of them in there all the time.