Not trying to sound like a jerk, but casual sports fans (and probably not-so-casual ones too) seem to equate calling plays in football to a catcher calling pitches in baseball. There are SO many variables that dictate what play is called, and even more that can make a play go well or poorly once the ball's snapped.
A case in point is our old friend Kevin Gilbride....the guy ran what we all thought was just a horrendous offense while here in Buffalo. Then miraculously at age 55 (or whatever he was), he leads a dynamic offense to the Super Bowl a few years later. I seriously doubt he didn't want to do the same things in Buff, he just didn't have the talent, match-ups, etc to make it happen.
My point is these guys have way more knowledge, information, and skill than we can imagine.