"Based on what the devs plan to do"--> Is there a roadmap somewhere? I have been following status report for a while now and I have not seen a document that gives longer term goals. It's probably intended, but just curious.
"current ratio of release" --> I don't think you can base your calculations on the current speed of development (or at least the one perceived by the larger public), it seems that the animation update has been a real issue both in terms of management and development (I obviously don't know the details). But it's probably safe to say that after it's implemented, they will be able to iterate faster and release more content. I'm not saying that NPCs should be just around the corner, but given how fast they were able to implement vehicles, it looks like the team is very efficient when the development is more straightforward.
As far as I'm concerned, when vehicles, fully animated characters and NPCs (even in a really basic form) are implemented, I will be 100% satisfied with the game. *waiting for stones to be thrown at me*