Private ownership is usually great answer to the tragedy of the commons. In a blockchain world the best solution is to change the incentives (what blockchain is encouraging to be done by paying for it) and UI (users don't necessarily want to make great effort to do something even when it rewards them more).

The blockchain reward system is quite good right now. I wouldn't do any drastic changes to it.

The UI is the thing what should be adjusted. The reason why some posts get a lot of votes is because they can be seen in the front page. If they were not on the frontpage/trending, they would still get a lot of votes but less than they get now.

Frontpage is creating too strong positive feedback loop for some posts that get a little bit of initial attention from the whales. When a post gets into frontpage, it's pretty much guaranteed to get a lot more votes.

My solution would be to individualize the frontpage for every user (maybe a combination of their feed and recommended posts that they may like). Trending page should be a little bit harder to see (a couple of mouse clicks) so that users wouldn't spend so much time in there (the feedback loop has to be made weaker).