I find that once you've been inside a particular topic area (general, off topic, etc) and return to the main page that topic area shows no unread posts. If you return to that area, though, any threads that you hadn't read are still marked unread for your attention.

I always figured the action on the main index was to take care of a 'been there, done that, didn't need to see everything' situation. That is, once you've seen the index for the topic area, you've seen what is has to offer (different than having read all the posts in all the threads).

I don't mind the current functionality- I kind of like it.
ymmv
<shrug>