Despite it's success, what's the main thing holding Steem/Steemit back?

Question originally asked on Musing.io - Click here to see other answers

I created a post about this, but it is nearly impossible for a plankton to receive a decent reward for curation. You can read my proposed solution here. https://steemit.com/steemideas/@giddyupngo/if-i-could-change-one-thing-about-steem-better-curation-rewards-for-plankton