Maybe you remember that I would support the implementation of a "convergent linear rewards curve". Concerning 'downvotes' I had the following thoughts (copied from my own post "My STEEM Vision."):

I think it's good and right that the possibility to flag (now called downvoting) exists in a decentralized social network. How else can spam or even worse, such as child pornography, be fought? I also think it makes sense in principle to be able to reduce the reward for posts that are extremely overrated from one's own point of view.
The crux, however, is that downvotes are often set for the sole reason of pursuing other users, solely because of their dissenting opinions or even completely independent of what they write(!), and denying them permanent visibility and any rewards. This is counterproductive to say the least and makes a devastating impression on newcomers who happen to observe such 'flag wars' or even get into them! We should be aware of this.
If it were up to me, ways and means would have to be found to contain 'flag wars' waged purely for personal motives. For example, a committee of respected users elected by the community and equipped with sufficient delegated STEEM power could be called in such cases and then decide whether the flags were justified or not.
In my opinion the suggestion to provide each user with a certain number of free downvotes so that spam (or overvalued posts) would be flagged more frequently in the future, wouldn't really make a big difference under the current conditions. I assume that only whales flagged more often than before, while smaller accounts would still not dare to do so for fear of retaliation.

Nevertheless, your idea of the "hybrid approach" is interesting and at least makes it somewhat less profitable to flag a lot, "just for fun".