What incentivizes down voting, though? Isn't it true that down voting does pretty much nothing for you in terms of making money within the Steem economy (besides the nearly immeasurable effect of distributing a small percentage of payouts back to the reward pool) and almost assures you that you'll eventually get head-hunted by one or more (probably many) of the accounts that you vote down? In other words, "SP wastage".
My thought on this is that you absolutely MUST find some way to incentivize "good down voting", something akin to the curation reward system, only in reverse, or you'll get more of what we have right now, regardless of having a separate pool for down votes (the fear of retaliation will still be there and with no real incentives to down vote in the first place).
Maybe a SMT for the down voting side of curation would solve this problem. Have it work just like up/down voting does in relation to Steem, except taking only down votes into account. Those who down vote earliest on any given post get the largest percentage of the down voting rewards for that post, with respect to their total SP, and they get considerably more the more SP that down votes on that post after them, with the (down vote) rewards pool distributing a fixed supply, irrespective of how many accounts, or how much SP, down vote(s) over any given period.
Does this type of SMT stand any chance of reaching a dollar (or even Steem) valuation capable of offsetting the fear of down voting retaliation? I think it's worth a shot.
Nothing incentivizes it specifically, this change is more about removing the disincentive from downvoting (which right now is that if you downvote, you're losing out on potential curation rewards).
I'm not sure how an incentive model specifically could work for down votes, but at least removing the penalty for down voting would (IMO) make for a better system.
But that's my point, we ARE inherently disincentivized from down-voting, regardless of whether you remove the voting power penalty or not - it's the fear of retaliation (flag wars) which indirectly hits you with a voting power penalty in the form of having rewards downvoted away by those that we downvoted in the past.
So my suggestion is that we counter that inherent disincentivization (or the natural tendency for the majority of people to side step the possibility of voting retaliation, or "flag wars", by simply not participating) with some form of incentivization, something like an SMT that rewards "smart (useful to the system) downvoting", in an attempt to convince a larger portion of the population to play this game in a useful way, which actually might bring something like a "real consensus" as to what is good or bad content.