From a usability perspective, I like the FR format, you can quickly see the thread titles, glance at which ones interest, or don’t interest you, see the posts and who posted it, without having to click the mouse. Sure it may look relatively spartan, but I prefer simplicity.
If there would be only one thing I wish they could add, it would be to have the ability to self-edit posts. Nothing worse than knowing you made a grammatical error right after you hit ‘Post’.
The bad thing about editing is deleting.
If I were to re-write FR I'd re-write it with virtually the same interface and possibly an even more simplified interface based on John's experience over the years dealing with the code. It needs no graphical bells and whistles. It just needs speed and stability IMO.