Dan Mullen wears a visor because he grew up a Florida fan and Steve Spurrier wore one. Much like the Head Ball Coach, Mullen used his play-calling acumen and creativity to go from offensive coordinator to head coach. Spurrier continued calling plays throughout his head coaching career because, well, if it got him there why would he entrust someone else with that responsibility.
On Saturdays you’ll find Mullen roaming the sideline with his play-calling sheet but he’s not the only coach that can or does call plays throughout a game.
Mullen has had the luxury of keeping the same coaching staff around him for more than a decade.