The problem with the purging of diaries and deletion of user accounts as I see it, is the lack of transparency. After the fact, a diary or comment that has been deleted cannot be viewed, and we are unaware of who's account has been removed.
This problem could be solved fairly easily by using what in messaging systems is called a "Dead Letter Queue". This is used for messages that cannot be delivered. The administrator can still view them, and try to understand what went wrong.
In this case, a Dead Letter Queue (DLQ) could be used to view deleted diaries, the rest of us could read them if we wanted to, and they would be off the front page. This would remove any concern over the integrity or appearance of the sight, but still give transparency to the entire operation, and a chance for peer review of the decision.
While I'm on the subject, a ratings system based on a trust model would help as well. Ie, being able to have a circle of trust that could be used to individually tailor what the viewer believes to be a good diary or post. A person or group that is interested in voter fraud would be able to rank diaries for each other, more or less independently of the rest of the community who finds this subject offensive. Being able to filter comments based on "what georgia10 recommended" or "what my group recommends" would give a more custom experience.
Last, it would be nice to expand on the open thread. What if, the top diary, or top 3 could be promoted to the front page once a day? This would allow more participation (we have the power!) and I think make the front page a more interesting and diverse one.