Rather than fixing hypothetical future problems, I would rather have work spent on fixing things that cause problems now, for example:
when you click on a permalink to a single comment (like those you find in your mailbox, or in the recent comments), the whole thread it's in is marked as read (and won't be in green any more)
There is no way to see the upovote / downvote split on posts and comments, only upvotes minus downvotes (though I'm not sure that would be such an improvement, it's just something a lot of people ask for; there recent "poll" feature may be a better way)
(unless of course you were planning on implementing, testing and submitting the fix yourself!)
It came to my attention that when you receive downvotes for your comments, your karma goes negative and you need to "pay back" to be able to post to Discussion or to Main.
Since new users start with zero karma, having negative karma seems to just encourage those with negative karma to create a new account. We don't want to encourage people to create superfluous accounts, do we? Therefore I think LessWrong codebase should be patched so that karma does not go below zero even with lots of downvotes.
What do you think?