What if you had some sort of 'downvote guidelines'? Those would be tied to a pool of SP delegated to a bot account. The bot could be governed by a jury system (a vote on dpoll maybe). If you invoke a jury(whitelisted maybe) and win, you get the downvotes erased plus a certain percentage. If your invocation is BS and the downvote is deserved, the bot downvotes you even more for wasting people's time. Each juror can get a small upvote from the bot on their vote submission. Jurors can voted in or out based upon their adherence to the downvote guidelines. In this you have a community driven system that could overcome abuse or exploits. To seed the pool, the bot could also be a witness vote proxy that tracked how much witnesses delegated to it. People supporting the jury system can let the bot vote on their behalf and then witnesses would be forced to delegate more SP in order to compete for votes. This would also have the side effect of making the top witness have the biggest SP investment in the platform. Perhaps there could also be a way to incentivize everyone else to delegate to it as well.