The only problem I see is people being able to use this to spam sites. I haven't downloaded it and tested it yet though, so it might not be possible. Just one thing to notice.
For all you scoop admins, if you didn't already know, there are a few vars to help control this. If you are using the dev code, they are in the category Post Throttle, if you are not, they are: max_comments_submit, max_stories_submit, rate_limit_minutes, timeout_minutes, and max_timeout. Read their descriptions, and adjust accordingly.
Another thing occurred to me, Smirks, does this handle errors well? Like, if I post a story with 100000 chars in the intro, and the limit on k5 is 3500, will it fail gracefully? or will it just tell me that it posted anyway? Just trying to create more work for ya ;-)
-hurstdog