I keep thinking about writing my own updates to blagg. My two biggest complaints about it are listed as todo's but they are starting to drive me nuts. The first is that it only uses post titles to determine uniqueness. The second is that it doesn't clear out old posts that aren't in the feed.
The final thing I'd love it to do is have a way to update posts on LiveJournal when they change, but I'm not sure if that is possible. Right now I'm forced to go and delete the old post on LJ and have it repost.