My inclination would be to maintain the status quo until there is a compelling story for how to deal with spam, self-voting, etc. I'd probably be fine with option 2 as well, but while the risk of introducing bugs by reverting to HF21 code is small it's not zero (the risk of bugs is never zero with any code change). I also agree with the people who say that most small voters are reluctant to downvote due to fear of retaliation, I certainly have felt that way about things posted by powerful people that I thought deserved downvotes. I also think that having people manually downvoting spam is a waste of resources -- if something can be automatically detected by software it would be better if it was done that way, we're better off as a platform if actual humans are engaged in reading good content, not trying to fight an arms race against spammers.