That's why I asked whether they can even give an accurate picture of what's coming next/soon though. Giving a list of when we can roughly expect features might not be feasible or a good use of their time.
We have a "general roadmap" of what's in the works. They've told us through various blog posts, patch notes, and forum posts what are the general features we should expect (kingdom management, perks, criminal enterprises, diplomacy, marriage, etc, etc). Anything more detailed than that is bordering along what I've said above. I'm sure the internal design document is very large and would take a lot of effort to curate to be acceptable to release to the public.
Maybe I'm wrong though and they have a roadmap on the way. I'm just giving reasons why they may not.