We don't need to kill the bots (that's not really possible in a decentralized, censorship free platform) All other services are full of them, difference is that Steem lets you earn for activity, so there's more incentive for bot operators to run them.
What we could do is to make proof of brain great again.
HF21 will give us a chance (to curate great content economically competitive to self-voting / vote-selling, to downvote mediocre content that was boosted by bots, etc)
PS
Come to SteemFest :-)
Unfortunatley, I believe HF21 will do the opposite. A greater percentage will go to upvotes, which is what the bots do! It rewards them and reduces the incentive for authors to post their blogs. In fact, you could create a bot-only scenario. Some bots auto-create crap posts and in collaboration the upvote bots then direct all the votes to them. A circular system that would harvest all the rewards, leaving little for real authors and authentic content. I would wager somebody is already working on this as we speak (if it is not already in place).
Thing is that currently content could be (thus is) irrelevant, because no matter the content self-voting (selling votes is pretty equivalent of self-voting) can bring easy profits without need to chose curation.
Sure, those who pay for votes most likely will earn less, but those who can produce high quality, original content will have a better chance to be noticed by users who are willing to curate such content, as the incentives will increase (now it's too easy to just sell votes and get better profits than bother with curation)