After abuse being an issue for so many years, I don't think relying on active user moderation is the right approach. The problem with needing active downvoting to regulate a system is that there is little direct incentive to act. Most users are apathetic and often will only act if there is a direct incentive to. In terms of abusers, there is a direct incentive to abuse. There is potential monetary gain to content generation regardless of the "value" of that generated content. While content production is relatively free and inflation distribution is funneled through content generation there might always be a conflict of incentives where the direct incentives slightly favors the abusers which makes this a perpetual battle.
I like that thought. I like the concept of incentivizing abuse control. You it has been tried with SFR. Although I know most of the people involved in that project, I was exactly sure if the mechanics. I am rarely sure about any mechanism of hive :)
But point is, what you have suggesting had been tried with moderate success before.