Display how many new threads/posts are in that forum (yeah, more queries, but... if your server can handle it, why not? And if it can't, use the default or other ideas).
Then, when mouse overed, display the last X (10?) threads/posts that are new. Clicking one of them takes you to that thread as it would currently. Clicking say the forum title in that display, will take you to that forum and only display the new threads/posts for that forum.
I dunno, just a few ideas. Of course, I have these ideas because I'm part of the 30% that don't use the current setup. But having options would be good, even if it were use options as to what they want displayed there, as clearly there's another 30%+ that use it the way it is. So I wouldn't agree with changing it, but I would agree with options.