My opinion, backed by years and years of research (by others) is that economic improvement cannot fix what is at heart a social problem.
Thinking you will find a solution to the harm wrought by those who act in bad faith by tweaking the economics is illusory.

Hirschman's analysis, like that of most political philosophers, underlines the existence of two dimensions of the human soul. Two dimensions which are complementary: passions ("social"), on one hand, interests ("economic") on the other hand. It is essential to keep in mind at all times this bi-dimensionality of humans and human groups
The only way to protect the platform and the honest people from the harm and exploitation of "bad actors" is by working on the social dimension. It's hard, it will never work perfectly but it has been proven throughout human history to be the only viable way.
What does that imply: create "culture" - federate people around a common goal (needs to be quite generic) and set of values. Think "Agile manifesto" for instance, if you want a concrete example of what I mean.
Then register "communities" which can each "translate" the generic goal and set of values into more specific goals and a more elaborated set of values and create a framework for communities to register and regularly be challenged to prove they are still there and doing their job.
Then let each community "shepherd" its members and take responsibility for them and their behaviors.
Ultimately, it will depend on users assuming personal responsibility for doing what is good and refraining, of their own volition, from doing what is evil. This is what, for instance, Jordan B. Peterson says.
I reflected on this before already, in this short post: Barcelona and thoughts about decency

No economic mechanism can save us if people on Steem do not display a sense of decency.
That implies caring 80% for your own interests but also 20% for the interests of the others here and of the platform
I'll try to write at least one post elaborating on this position further