The acting sometimes feels rigid, and some of the extent of situations seems unrealistic without additional context. Between the 3 (current) films, there's also a lot of filler with little plot progression. That trend continues in The Black Rider.
In order to keep up with the fight scenes of the first two movies, a lot of needless filler was added, pushing most of the real plot to the second half of the film. The fight scenes also weren't very well-paced and were like long breaks from the plot instead. They could learn a thing or two from Marvel on how to keep things flowing without the awkwardness.
The religious message is prevalent, though at times used with questionable accuracy. As with the first two movies, the Christian message is awkwardly juxtaposed with a protagonist with a penchant for killing. Though I have to give props for at least addressing the issue, it seems to be completely forgotten for the rest of the film.
The main turning point, both as the MacGuffin and in the tone, is the Shepherd. This is the only main character who doesn't seem to be awkwardly juxtaposed with the message of the movie - though he's also far from an action star.
I love ruminating on the book this movie is (loosely) based on as well as movies that attempt to interpret / depict the events. Though not quite cringe-worthy, the movie just doesn't have much going for it due to feeling like a single, stretched-out episode. When the series is complete, an abridged version might be better worth watching.