Can a "combined view" be created for forums with subforums? In such a combined view it would be possible to read posts and add replies, but not to create new threads, as new threads have to be in a subforum (or maybe in the main one). I think that would keep threads tidy and organized, without necessarily adding further depths to browsing.
Here is an
example (under "Specialized Terminology" there is a "Combined view" link). In that link, the combined view is implemented as a predefined search, I wonder if there would be another way to do that.