Glebb--Donald Byrd and Gary Griffin did great work. Part of the reason the show is so moving, despite the written-by-committee score, is the way it moves and the way it is paced. The direction and choreography are flawless, which can't be said for the direction and choreography of, say, Wicked.
But mostly it's the magnificent performances that make the evening so powerful. If it were only LaChanze, I would say the credit goes only to her. But she is incandescent and the rest of the cast rises to her inspiration, so credit must go to the director and choroegrapher for the way they created the ensemble.