I think if a vote without a comment (not spam) was worth less than one with a comment, you might see more reading.

Interesting idea!

I don't understand the whole idea of the 5 minute window.

The idea is that without that 'curation window' bots could always vote faster than everybody else.
If with curation window bots vote instantly/very fast they will get no/a low curation reward, so that they have to wait and try to find the best moment to vote. And that's not so easy, because if they upvote for example exactly after five minutes, that doesn't necessarily mean a maximal curation reward in case many other users have upvoted the post earlier (for example after four minutes).

However, real curators have no chance to read, evaluate and upvote a post within five minutes, which means that auto voters get the biggest part of the curation reward in 99 % of the cases.
I think that either we should have a very large 'curation window' where it would be very difficult to guess, when an upvote leads to maximal profit or no 'curation window' at all, so that curation reward only depends on the vote weight but not on the date of the upvote (in my opinion it's a complete myth ot the manual curator who spots precious content early and should get rewarded for his efforts - that may happen as an exception, but most of the time auto votes come in early, whereas manual curators follow).