I doubt software could handle the problem. It would likely require some sort of consulting SWAT team to handle the issue, since it's such a policy and behavior driven problem. The reason HN has been the most successful in fighting the ES has been through the culture the PG built. Trolls are not tolerated, and off topic articles are punished ruthlessly.
If you think about it too hard, it seems a little brutal, but you have to remember that this is just a discussion board.