Focusing on 'proof of attention' fits well with Steem's goal in the attention economy. Instead of just rewarding content, 'proof of attention' will encourages active engagement, which can lead to more meaningful interactions. You’ve suggested some ways to keep ranking standards and attention metrics strong. These can improve the Steemit's content curation and motivate real community participation. Also, using comment ratings and upvotes can help measure the quality of engagement. This could put more value on active participation, like thoughtful comments and replies. As a result, both content creators and readers would be rewarded for encouraging discussions and deeper involvement with posts.