For hbd as debt, wouldn't every stakeholder be on the hook when inflation dilutes their holdings?

Well... first of all you don't seem to be factoring in that HBD printed from the reward pool and issued to blog posters was supposed to be Hive in the first place (and that option is available in the form of 100% HP rewards). If it never gets converted back into Hive that's free money for Hive, and if it does get converted back into Hive that's exactly as much inflation as we agreed to in the first place.

One must also factor in that Hive can be aggressively burned to create more HBD in a pinch ($1.05 HBD price and beyond). On top of all this, we must also factor in that USD is losing value every year, which brings me to my final point.

Irrespective of what the price does

Nope: veto

You don't get to say that because USD going down in value from inflation inherently increases the value of Hive which is the underlying collateral for all the debt. When the value of USD goes down: Hive will go up against it and we owe back less debt. I'll be talking about this a lot after the fed gets forced back into infinite QE and a bunch of easy money floods back into the economy. The value of our collateral is one of the biggest determining factors across the entire discussion.