If I understand this right, one becomes a curator by voting for posts from someone else? Then most of the people on hive are curators. No matter if they actively curate, or just set an autovote. They are curators. To pay 75% of the rewards for curators is overdone imo.

Creators need to invest much and much more time to write a decent post, and draw attention to their blog. Yes for the last part you need curators again. But both are very much needed. However, curating can be very easy by just setting auto votes ... YES I know that's not what you mean, but let's be realistic here. The majority will go for this option and farm curation rewards. While the content will get less because people stop creating because the creator earns much less, for much more effort.

Not something I would choose for.

Both are needed, so imo 50/50 is the fairest option here.