Vadim,
In a previous thread a few months back, we discussed the design of forums.
The reason for forums being separate from bboard is that bboard had serious implementation issues, specifically with respect to overuse of objects and permissions. The goal of forums is to progressively recreate the functionality of the 3.x bboard package.
The reason we left out categorization of threads at first is because there was talk of a generic categorization package - that would be the *right* way to go about this. I agree that we should use categorization, but I think it's better to hold off on categorization until we've implemented it correctly.
The recently answered questions and search by thread features can definitely be implemented easily - although just for completeness's sake, I should mention that search by thread was not implemented in the 3.x bboards.
All of this is good feedback - part of rewriting a package is figuring out what is truly useful to rewrite. Clearly there are missing pieces: forums is a work in progress.
