"Will there be authors that will offer more than 25% curation rewards on their posts?"
I would. In the hope of getting more upvotes.
"I don't think I will, to be honest!"
Why not?
If you think about it, it would be a win-win situation.
Both the authors and the curators would earn more rewards.
50/50 will only eliminate bid bots and nothing else. Cycle jerking/vote exchange will continue.
I think mainly high SP accounts that currently get high votes will benefit more with this system as they will be targets of many curation snippers