Well the first 20% is about 4 characters, not in subplots, but are in the same plot, but there are multiple things going on that they have to figure out. They are figuring out why the villains are doing what they are doing and how to deal with it. This gives the audience a lot to think about since the villains motives are very complex, and it raises a lot of debatable issues, which is what a lot of the story is about. Then after that 20% is established and they have decided what to do, then the racing to solve the mystery gets started more so. There is a lot of action in the first scene, but none after till after 20% at least. Just setting up the issues and the characters study and debate them.
The villains aside from the opening action scene, are not seen again till halfway through or a little over maybe. Haven't gotten that far yet. But the reason why they are saved for later, is so some twists and turns can happen from the hero's point of view. Then after those are over, the villains come, and are given depth and we get to know them, and their unique motives. Will the viewers also think that the villains are not given enough depth, since they have complex issues? The viewers will have to trust that they will be later on, since they are not seen again after the first action scene, till halfway through.
I don't go by the three act structure. I just come up with the story and pack enough twists and turns in and be sure to have a long building climax, instead of a quick one. So does it still sound like the viewers could likely be drawn out? I was hoping the issue dealing would draw them in.