At least there you are finally saying that the net effect of hf20 is to narrow the gap.
I still think you are missing the big picture. The smallest accounts are always going to have the least amount of votes coming in shortly after posting and people jockying around for optimal curation reward vote time. The largest accounts are always going to have the largest amount of votes coming in shortly after posting and people jockying around for optimal curation reward vote time. If the early curation rewards are returned to the pool, the largest accounts will "send" proportionally more reward back to the pool - it decreases the % of the pool dominated by the large accounts.
If those rewards stay in the post pool, whether it is in the author reward for the post as in your proposal or the curation reward for the post as in earlier proposal advocated by @davemccoy among others, it doesn't do anything for the smaller accounts - the % of the pool dominated by the large accounts stays the same!
In effect this argument is that smaller accounts will be more effective at discouraging pre-fifteen-minute votes (relative to total votes received) than large accounts. That seems unlikely to me since larger accounts are almost universally more sophisticated users.
I've been pondering a project to vote accounts with large expected payouts at minute zero to create this effect intentionally. I think once more people are paying attention to this issue the consensus will be that it's incredibly stupid that I will be able to do that. But we will see.