Here's my wishlist:

As much trn functionality as it seems to be worth coding-- in particular, the ability to default to only seeing unread comments (or at least a Recent Comments for posts as well as for the whole site) while reading comments to a post while having easy access to old comments. the ability to default to not seeing chosen threads and sub-threads, and tree navigation.

If you want to find out how people generally use the site, I think a top level post asking about it is the only way to get the questions noticed. If you post it, I'll upvote it.