For the time being, maybe this will also come in handy for what you would like to see:
- If you create a message board for a specific project page, you can open up sub-categories within that message board. (By looking into the edit options within)
- You can also create 'tags' for each of those sub-categories (within their corresponding edit options)
With those options, you can easily create content-focused categories and topics for you and your members.