Yes, reading your comment made me remember one proposition I really liked actually!
Separate passive investors to their own reward pool so they don't diminish the efforts of active curators! If there are people who only want to maximize their profits from investment, let them, but we shouldn't let that behavior effect everyone else negatively and forcing them to join since there's no other good option. If we do this, there will be more curators, since they can actually affect what the trending looks like. And as our content discovery actually starts working, we'll start getting more members. And as Steem Power will actually have effect after this change, there'll be more demand as well, both for passive investors and active users which will drive the price up. So in my mind this is a win win for everyone, other than those who want to see Steem not succeed in a major way.
Sounds like an SMT backed with an Oracle could be the solution here? That way the post rewards as viewed by the SMT may choose not to include bot votes and self-votes.
Yes, SMT's could try a lot of different schemes, and I'm also interested in making one that focuses solely non promoted ecosystem.