Joe Posnanski puts it quite sufficiently in this passage from his SportsOnEarth column Masterpiece Theater:
Before Steve Sabol, mud was mostly a nuisance for a pro football game. Players slipped in it, slogged in it; mud covered their bodies so you could not even tell which player was on which team. After Steve Sabol, mud became something ennobling; it became the canvas to paint Gale Sayers’ grace, Jerry Rice’s precision, Jack Lambert’s force of will, Johnny Unitas’ high-tops.
Before Steve Sabol, snow and ice made football boring and miserable to watch. Nobody could complete passes in that stuff, nobody could gain traction. Heck, you couldn’t even see the yard markers. After Steve Sabol, football in the snow and freezing cold separated meek from mighty; you could not forget seeing Dallas’ Bullet Bob Hayes trying to shove his hands inside his pants just to warm them, and you could not forget seeing Bart Starr push his way into the frozen end zone.
Before Steve Sabol, pro football was a game without mythology. It was a good game, one gaining popularity all the time, but it lacked the poetry of baseball, and it lacked the history of boxing, and it lacked the soul of college football. What was pro football anyway? What did it even mean to be a pro football fan?
A big part of the greatness of NFL Films was that Sabol found the right voice, John Facenda, to narrate them. I don’t think it is a coincidence that NFL Films, while still good peaked in the 1970s with Facenda reading Sabol’s copy. Then again, part of that might be my own nostalgia for the NFL Films that were around when I was younger (even if they predated my time watching football/breathing). Another strength of NFL Films was incorporating the local radio broadcasters instead of the national ones. The local flavor and theater of the mind aspects of radio complimented the slow-motion film well and certainly raised the profile of the radio teams.
I pulled up a few videos, including the first NFL Films production with Facenda. Sabol wrote and produced “They Call it Pro Football” which is credited as the breakthrough for NFL Films:
Sabol also wrote “The Autumn Wind” poem about the Oakland Raiders: