For me, there is never a right or wrong here because that is irrelevant when the free market has the final say. We just have to get to a point where they say it is best for the community. Any imbalance causes abuse in either direction.

Maybe we have something along the lines of what you're saying to identify potential rampant DV abuse. Give away for the community to then take "action" against said abuse. I'm trying to think of things that don't require messing with the base code, something of a layer 2 of sorts. So maybe we use the DAO, make a prop to power up x amount of HP. This account has to be not owned by anyone and has to be controlled via a threshold mechanism. IE, enough of the community, voted to reverse this DV with an upvote from this anti-abuse bot. This line of think can be done just using DAO's and outside code. The tricky part is making sure no one has access to the keys, which I'll leave to more aware minds on how to do that code wise.

If we reduce the number of free DVs, the attacker can only do so much. Where the punishment comes is when the attacker runs out of juice, the bot is countering the votes, now the attacker has 2 options, to stop or keep abusing, which will then cost him VP, which hurts the attacker's bottom line.

So I haven't come up with a solution to punish outright abusive DVs, but this is a way to counter their behavior and corner it so no damage can be done with a short lease of what they can get away with for "free". Eventually, it'll just be a waste of time of them spinning their wheels, and they much off.