First: I hate the topic font size, the paltry 20 topics per page limit, the wasted space on sidebars and headers. Enough people have complained about this that you should be on the case.
Moving on, though, one thing I find myself sorely missing is the ability to see, at a glance, who's responded to topics and in what pattern. (i.e. popular topics may be flat, with lots of replies from different people, or deep with back-and-forth bickering between two users, or another shape entirely)
This was possible with the simple but brilliant tree view of the old chowhound. User tracking is not an adequate replacement. Have you considered an NNTP (newsgroup) interface to chowhound so we can interact with the discussions in our own preferred interface? This would be a service I'd consider paying for.