The Performances carry the film.
That's no disparagement to August Wilson, because the entire film centers around the dialogue, but it is not unusual for a play adaptation to be watered down to appeal to a wider audience or else appear jarring in a film/television setting (See: Tyler Perry productions). This film was successful because the cast handled the pacing, delivery, intonation and overall language of August Wilson with remarkable effortlessness. Anchored by the star turn of Denzel, I can honestly say I was moved emotionally, and all done without any special effects, suspense, action or light sabers. Well done denzel.
Que Sera Sera