The HBD idea is interesting, but it's still just as game-able by sybil attacks, assuming the voter is willing to fund his sockpuppet accounts for their votes. And that probably leads to a worse voting system, since it seems more likely to me that voters who are paying to vote with sockpuppets would be more likely to do so in order to generate a personal return.

For DHF expenditures, I think it makes sense that the votes are stake-weighted, since the more stake you have, the more you have to win or lose based on the results, and stakeholders are in some sense "funding" everything else by being willing to hold Hive tokens instead of selling them, which drives their value.

Despite that, I don't think stake-weighted decision-making has to be the "only-game-in-town" on Hive. The second layer reputation app I plan to create, for example, will be totally divorced from stake-weighted voting. The only connection to the first layer in this app will be for resource credits to create transactions.