i guess you missinterprete the current idea - if you have StakedHivePower, then you take part in the ecosystem of Hive while you earn the HBD Interests with it. Sum of both should not reflect in a negative return. The HIVE you stake is not stable and fluctuate, but possible it goes up and you earn more for curation otherwise when hive goes more down, you get less of it.
Investments always comes with a risk - the risk itself gets reduced heavily once you start curating and use the Ecosystem and be part of the community.
thats what i think about it.
I don't like the part where you have to own bigger sums of HP than most users have to be eligible for the HBD rate. Yep it can be dynamic but the proposed steps are unfair and they only benefit those who already have big bucks.