The idea of incentivising late voting sounds great but in the end all it can do is to move the bot playground from the first five minutes to the last five minutes.
Yes, that is exactly what we need to do (imho). The current 'problem' with bots is that they accumulate dozens of votes at the 5-minute mark for a post that might be complete garbage, but happened to come from someone who had some good previous posts. In other words, they add noise to manual curation, thus decreasing the signal-to-noise ratio. Delayed auto-votes can amplify the signal (because they have time to evaluate and filter noise from the genuine signal). In that sense, the bots become a resource rather than a liability.
If the bot playground is in the last 5 minutes (or the midpoint of the voting period, as I've suggested), then the bots actually have some really valuable information available to them, because the bots can evaluate the voting patterns of everyone who voted before them (and even cross-evaluating how they voted for others).