Overall, I like this trend. There's still an incentive to compete over curation rewards but the gap is narrowing so those who are not actively front running bots or doing it manually are not completely left in the dust.
I think if profit maximizing curation (even if it's profit maximizing curation, it's still far better than vote selling, circle jerking, and arguably not a bad thing at all) is performing around 70% of voting rewardings, then with the free downvotes hovering aorund you're likely better curating than vote selling.
The trend is positive, I’m not sure how much closer the high and low averages will get though - this could be about it.
I’m not against trying to curate for a little extra steem if you were likely to vote the producer anyway because of consistent, interesting content. If the content becomes over-rewarded or uninteresting then perhaps CR will lower due to downvotes / the vote should be moved.