That would be super interesting (the reverse curation on comments). Honestly the frontends could probably do that just by automatically setting beneficiaries to the original poster.
One thing to be worried about though is that the 25% curation rewards would still come off of the comment, so the poster of the comment would only get 50% of the reward. 25% curation, 25% original poster, 50% author - not to mention any % based on platform which could make it lower.
Yeah I've been looking into 'beneficiaries' functionality as a way of implementing the reverse curation.
Good point about the curation split. I still think it's fair, as the OP is the ultimate enabler of those comments further down the line.