There's a lot of great ideas in here. I especially like the idea involved in characters not being in communication or combat happening 'off-screen' so to speak to create a sense of tension. There are a lot of great instances of using rule examples to help build out the world you're imagining like the example you included of a group using RAM. Will definitely be trying this out with my game group and I look forward on seeing how it develops if you choose to keep working on it!