If you move the sweet spot elsewhere, everyone playing optimally is going to withhold their vote till the sweet spot so any information available to bots is coming from poisoned wells.
OK, in the real world not everyone can adjust so shortterm you can mine some useful info from good curators. Longterm, they are going to leave when their rewards go down.
Trying to create multiple sweet spots is just an effort to make the whole process of wearing the manual curators down last a little longer.
My reference point is not the current system, btw (community agreed it is flawed months ago - not necessarily saying there is a consensus on improvements). My reference point is the system where curators and bots share the first place between everyone voting in the first N hours. In lab conditions (everyone optimal) it boils down to linear (LEO) with shorter voting (no one bothers to vote outside window). In the real world it allows both camps to cash in any advantage the casual players leave on the table by voting late (to be nice and send the rewards to authors that deserve them).