Maybe I'm misunderstanding, but the graphic above wouldn't actually stop the wheel from moving forward (counter-clockwise), but it would prevent backlash or reverse (clockwise) motion. Now if the sprocket wheel was turning clockwise, it would most certainly only allow movement through one notch each time the lever is released, But to release the lever, you'd need some other mechanism to lift it up far enough.
I'd think that for a "best case" scenario, a large drive wheel that engages several sprocket holes from the top would be the easiest/cheapest to implement. That single wheel would spread any force over several sprocket holes, and if engaged from the top of the hole similar to the toy projector, it would avoid some issues with worn film. Additionally, that wheel could be used as the reference for when to take each image similar to the original Kinograph.
Maybe via having a large drive wheel as I've said, we could devise an approach that pulls the lever up based on the movement of the main drive wheel rather than from film tension?