So how do you fix it? I don't really see another way to rank large amounts of stories other than points. Sure, you can try to detect cheating, but you want a minimal amount of false positives, too.
Edit: missing word
Edit: missing word
I am fan of adding randomization. It was previously proposed: show few random new items on a front page in random places, maybe with a little threshold.
I was thinking about community page destined to fork. After community reaches certain threshold (size, activity) there is automatic fork and 2nd generation community is created. Some algorithm adds accounts for certain users and blocks some other users from account creation. It's just a pipe dream...
We tested this idea (though we didn't roll it out for everyone) and the results were terrible. The median story is too low in quality for randomness to add value here. You just end up planting junk on the front page and annoying people. From that we concluded that there needs to be additional filtering, be it by algorithms, humans, or a combination.
Obviously still cheatable but would require more (i.e. easier to detect) votes.