Sometimes there's necessity in predictability.
It's very easy to criticise Just Mercy for being similar, maybe overly so, to so many legal dramas that have proceeded it. Such criticisms are not unwarranted and viewed purely as a piece of entertainment, it's unlikely you'll find anything in Destine Daniel Cretton's film that you haven't seen before.
In terms of its story, however, it carries a message that bears repeating. And it should be repeated, tirelessly, until the world in which we are living in changes. There's a superb moment in this where Michael Harding, playing sheriff Tom Tate, warns Michael B. Jordan (as Bryan Stevenson) that he isn't cruising into his "redneck town" to rid himself of no "racist sheriff".