The problem with Steemit are the whales.
What would I do if I were a whale? Very simple, I would sell almost all of the Steem I earn, because I produce it too easy to keep it and I do not need more SP than what I already have to continue earning a lot of Steem.
What you have to do then is to reduce the proportion of Steem gain achieved by those who have more and increase the proportion of those who have less. How? You could apply what would be a kind of progressive tax on profits. Whoever wins the most, the highest percentage of retention has.