Saw it two days ago, I'll post my thoughts.
Honestly I was a little disappointed with the film. The acting is solid throughout and the production quality is solid throughout but the film itself lacks the level of substance I was expecting. The main question in my head after I watched it was, "Who is this film supposed to be directed at?" Looking at the film's namesake and what "Birth of a Nation" represents in this country, I pictured this film having a lot more to say about the mentality of the white society that not only permitted chattel slavery but endorsed it.
I'll backtrack a little bit to make another point. IMO slavery films in general are by definition targeted at white people. The horror of slavery is not old - let alone new - to black folks here in America. White people have been raised to forget what these films (supposedly) aim to make them remember and confront. That being said, Nate Parker's Birth of a Nation suffers the same problem as the other slavery films (12 Years a Slave, Django, etc.) that came out in the last 20 years. The only way these films understand how to communicate with their intended (white) audience is through violence. The emotional set-pieces of Nate Parker's film are almost all predicated on extreme acts of violence committed by slave owners on their slaves.
My problem with violence being the driving plot device in this film is that the violence is a symptom of the mindset that empowers these slave owners to act this way. The mindset is the root problem, not the violence. When a white audience watches a film like this one, the only thing they are being forced to confront is the barbarity of the violence. A white person can watch this film and genuinely cringe at the violence while thinking in the back of their head, "we've come a long way from this."
But what about the barbarity of the slave owner's mindset? Have we come a long way from that? The original Birth of a Nation was released a full 70 years - a lifetime - after emancipation. What is the difference between the mindset on display in that film and that of a slave owner? There isn't one. What was the difference between the mindset on display in Jim Crow and the mindset on display in slavery? There wasn't one. My point being... What is the difference between the white mindset of 2016 and the white mindset of 1916? This film took on the burden of addressing that question when it took on the namesake and imo it failed to address it.
The narrative construction is a big part of where the film lost power... Nate Parker's performance is good but the choice to make him the singular focus of the film AND make the violence the focus of the film was a poor choice imo. Nat Turner did not rebel because he witnessed unspeakable violence, he rebelled because he saw that the mentality that enabled slavery was a chronic disease that could not be treated with sermon. The elephant in the room is that the white slave owners are sick but they can't (and don't want to) see that...
... The same way the white audience in the movie theater can't and doesn't want to see it either.