I agree what you proposed but I'd also make one more change. Make it so that curation rewards are also paid out 50% SP 50% SBD so that curators can also earn tokens which are faster to withdraw and swap for other coins/fiat. Also, why not limit the amount of SP that an individual can possibly use to upvote themselves and incentivise them to upvote a range of authors and not always the same ones. That way it would be more difficult to cheat the system by using multiple accounts. The hardest thing with all of this is to do it in a way that not only retains but also increases the value of owning SP