The 'curation window' of only five minutes!
Nobody who is upvoting manually rather than in an automated way is able to find new good content within the first five minutes after its appearance.
Not to speak about reading, evaluating and vote it with a "fitting" reward.
That means most curation rewards aren't earned by real, manual curation but by auto upvoting the same authors again and again, and most of the time the 'curator' doesn't even know what he is actually rewarding.
Don't get me wrong; Just like many many others here, I have quite a few persons on autovote as well. But the fact I'm using it doesn't mean I actually think it would be better for Hive as a whole, to enlarge the curation window.
I wouldn't mind some kind of experiment without a curation window at all considering that hopefully one day, posts will all be evergreen. It makes no sense to have the early curation window if a post can be open forever.