The answer is simple, at least to me.

Change the stupid mechanic of first voters getting more curation, just have it be determined by the vote values. Remove the pointless 30 minute scaling curation and make it 0 minutes.

50% curation/50% author reward. This should be self-evident in how it will encourage large SP holders to be forced to shitpost less.

Also, make curation and authorship give the same TYPE of rewards. It is banal to say the least to have curation only give SP while authors have the option of liquid SBD. Give both options to curation as well, or have both only give SP.

Some tweaks to power down time (probably shouldn't be 0 days, because hacking could be far more damaging to users) will also make powering up seem like less risky of an investment as well compared to straight trading STEEM.