I was disappointed with the outcome of Zapl. The problem I think was that tweets were equated to other posts on steem and hence there was a difference of opinion regarding content size and rewards eligibility. A dedicated platform short size content might address that. May be an SMT for content on Steem that is less than 240 characters so that the actual steem reward pool is not touched will change the odds.
Steem has better private key management compared to other projects but is still complex for a normal user. Custody is coming to cryptocurrency and that might solve this problem as well.
Custody is the current holy grail! Not only would it solve the problem of account management for most people, but it will open the way for real investment from the larger funds. As I understand, they can't invest at the moment as there is no qualified custody solution at the moment, which would leave them exposed in a big way if anything went wrong.
Edit: one of the many holy grails! There is much to do better before mass adoption can happen...