Race conflict, class conflict
While it's obvious that Shadrach deals with the mistreatment of blacks in the Southern USA, it more or less glosses over class relations. The narrator, a young boy from a wealthy background, goes to stay with some dirt-poor friends of his, yet the culture shock is never really addressed. How does his host family *really* view him and his parents? Not necessarily with hatred, but certainly there would be some discomfort.
Oh yes, and one more thing. Hollywood always needs a love story, no matter how stupid. In this case the narrator fancies a young girl, but this contributes absolutely nothing to the plot.