Thank you for the clarity with which you lay out the situation and proposed solutions.
As for HBD, @demotruk offered an alternative perspective in a comment responding to the recent post ( https://hive.blog/dhf/@threespeak/how-to-reduce-hives-inflation-problem-our-new-dhf-proposal-voting-criteria-hbd-apr-and-a-proposed-value-plan-sop ) which I think is worth repeating here:
A drastic lowering of HBD APR at this time may have unintended consequences. It may be highly inflationary. Hive stakeholders do not want HBD being converted during bear market, this is highly inflationary.
Buyers of HBD are compensated for risk with high APR when staking. Risk with HBD relates to the debt ratio, it is higher when debt ratio is high and lower when debt ratio is low.
Sound monetary policy for HBD would be commensurate with risk AND relate to the ideal outcome for stakeholders:
HBD should be converted when Hive price is high, reducing long term inflation. Therefore APR should be lower during bull market.
HBD is less risky when debt ratio is low. Therefore APR should be lower during bull market when debt ratio is typically lower.
HBD should not be converted when Hive price is low. Therefore APR should be higher when Hive price is low to avoid conversions and high inflation.
HBD should compensate for higher risk duing bear market. Therefore APR should be higher during bear market.
Hive witnesses have taken "stability" approach, which is poor economic policy for HBD. The price of HBD should be stable, APR does not need to be.
If this analysis is sound, then a dynamic APR would be beneficial IF interest rates go down as the price of Hive goes up and vice versa...
I suppose it depends on whether it is preferable that the Hive that has already been created to support the interest rate be kept locked up as HBD savings at the expense of creating yet more Hive to support the high interest rate during bear markets, or whether it would be better to release the floodgates by lowering interest rates, flooding the market with HBD-Hive conversions but slowing down the minting of fresh Hive...