While it would prevent limited cases of less-than-ideal curation, I don't believe this would be a net positive. More people would lose out in both post rewards and curation rewards than Hive would gain from limiting intentionally-late curation.
I often find myself voting on posts 2-5 days old because I can't see everything as it comes out. I would be less likely to vote on those posts if there were a severe curation penalty. And those people posting would lose out on my vote and any other late-comers' votes.
Furthermore, this would incentivize bot voting even more.
Less-than-ideal curators are easier to spot and counter than shaking up the curation system to this degree.
Yeah, It's adding complexity to an already overly complex system.
I'm still in the camp of removing the curation reward entirely.