It is useful to think of Leo approach as an extreme case of the system that is being proposed (the all-timestamps-equal first window extends to full time, the post-window time-gamified voting shrinks to zero).
I claim that adding the second window keeps all the upsides of linear (as long as the first window is long enough), anyone feel free to dispute this and/or point out downsides that the second window introduces.
The number of curators will drop (perhaps significantly), but the quality of the curation might go up.
I do not think Leo suffered such a drop but for the sake of the argument - if the drop happens the danger is that noise (auto or manual - does not matter) prevails and noone can tell which high payout posts were voted by quality curation and which are random events.
(This is an actual danger for the new system as well if too many votes are being casted in the first window).
when you can just let those who opt out of curating earn their 50% reward?
The more people opt-out, the more power of author reward allocation goes to those who vote. Only good if everyone is an honest curator. Self-voting and vote-buying (open or concealed) are getting more efficient.