Ditch the inflation-funding rewards. This one's crucial. I believe inflation funding on a common rewards pool is a major contributor to Steem's failure.

And,

The other, more insiduous drawback is people view the reward pool as a [private] public property that is waiting to be abused for selfish gain [whales encourage indiscriminate downvoting in order to boost their own share of the pool-pie], in various ways. In a way, it reflects some of the downsides of unfettered communism combined with unfettered liberty - the worst of both worlds. This has led to a lot of toxicity and abuse on Steem.

Well stated.