This review from AV Club was kind of my big fear for the movie - well, other than overexposure of Emma Stone ... it seems like a preponderance of "Civil Rights" movies follow the "white [girl] acts as conduit as black folks rise up against cardboard cut-outs of injustice!" trope.
I guess I shouldn't expect subtlety from Hollywood, but would the overall story really change if the "Anonymous" author was black?