What is needed, in my opinion, is a decentralized annonymous proof of brain CAPCHA. This could be made a service for those witnesses presently not in the top 20 to deliver for some small reward.
This would help stem, in my opinion, the production of counterfeit steem as outlined in a recent blog post of mine...
https://steemit.com/steem-network/@novacadian/where-is-the-trust-in-proof-of-brain-mining