I can see a problem with this type of thing in that people with lots of money coming into Hive, or people who have lots of money currently, just upvoting it for easy APR. There isn't any check or balance to that except someone downvoting the HBD Funder comments(which it looks like Kenny is now and maybe a few others).
I don't see any risk of it being upvoted just for easy APR. As I mentioned elsewhere, I could achieve the same or better "easy APR" by randomly following a voting trail (something I believe a lot of large stakeholders do, because it gets hard to distribute rewards from a large stake effectively once your stake gets too large). As it is, my APR for curation rewards is a little smaller than if I followed a trail, but I consider it worth it because I'm a strong believer in building up more funding for future marketing and development.
My argument is more from a consistency mindset, in that we should try and encourage all funding stuff to go to the DHF instead of upvoting comments.
The mechanism that Hive lacks right now is a way for stakeholders to dynamically vote for how inflation is directed. Those numbers are currently hardcoded and can only be changed by a hardfork. A long time ago, @smooth suggested we have a mechanism that allowed for this, and I've always liked that idea, but like all changes it would require more work and testing and could result in unexpected problems. I've always considered voting for posts and comments that fund marketing and development as a good compromise on that idea, because it doesn't require code changes.
I spoke with Smooth about this question of dynamic inflation pools only a few days ago at some length. He said he still thought it was a good idea but that he didn't think any decision makers in Hive were interested in it. I put a strong case for implementing something that regulates the public image of the reward pool on Hive and ensures that percentages allotted to each category of reward are adhered to. People look at investment trackers to identify projects to put funds into and they often list the percentages that Hive pays to witnesses, the reward pool and the DHF. If potential new investors look at those percentages, decide they like them but then come here and find out that the reality is quite different - with developers syphoning funds from author rewards into developer rewards - many will just drop hive into the 'scam' bucket that they are primed to do with all projects they investigate because so many really are scammy.
Overcoming the negative PR accrued by Hive due to Steem and other reasons is going to require intense focus on every single 'small' opportunity to tick all the boxes of people who check Hive out. I have a hell of a time getting anyone new to come from web 2.0 to Hive at the moment.. It was similar with Steem, but actually even harder with Hive. As a marketer, I will say clearly here that no stone can be left unturned when dealing with these issues.