I have a feature that I would like to see which would probably fix all of the spam problems that people have been having...
I would like a way to close comments easily. As I see it, there is no reason for comments to remain open once the entry in question falls off the homepage as the discussion for all intents and purposes is over. However, it's a pain to go in and close the comment thread and rebuild entries one-by-one.
As such, I would suggest that the power-editing feature include the comments field to make it easier to close the comments en mass. The other suggestion would be to include within the configuration an option whereby comments would be automatically closed for any entry that was no longer on the main index page.
Most of the comment spam that I've seen has been on older entries rather than recent ones. If a blog only has a few posts that are open to comments, this would reduce the size of the problem considerably.