What other solution is there ... ?

I still would have the idea to implement two different reward pools, one for 'stakers' and one for real curators and authors.

I think if someone considers themselves purely as investor they should be able to just stake HIVE in order to earn interest but after this decision shouldn't (be able to) upvote (or downvote) posts anymore which anyway they didn't read at all.

However, the ones who would choose to be in the curator/author pool should have to do real curation work which would mean to seek, actually read, evaluate and manually upvote posts that they really like.

That wouldn't completely solve all problems (for example some whales might decide to go for the curator/author pool, even if staking would be more beneficial for these users with huge stakes), but as we are 'brainstorming' here I wanted to mention this idea.