Clearly, you are stating then that a design decision was made to allow for the loss of coins because the total quantity of coins is unimportant. That is simply an indication that you are not reading what I have written.
It is one thing to design a system that allows for division of coins into ever more granular tokens, and justifying a design decision based on that. That, however, does not address the issue of increasing uncertainty in the system as it evolves.
Please show me in the papers written on the subject where it explicitly states that a design decision was made to allow and encourage increasing uncertainty in the system over time. If you can do that, I will accept that the original designers intended increasing uncertainty over time.
Again, it's not about increasing granularity or increasing deflation, neither of which are issues. It's about increasing uncertainty.
I think this is an excellent point which I missed previously because of all the distraction related to restoring the lost coin and the common misconception that the loss of coin itself is a problem. I think you undermined your argument in the first post by arguing for more than was strictly necessary to achieve these ends.
To remove the uncertainty you simply need to take the coins out of circulation forever, it's not required that they be remined. Otherwise you end up with another kind of uncertainty: e.g. say bitcoin manages to deflate to the point where 1 BTC = $1m in todays relative value... and a ton of lost coins miss their long hearbeat and show up mining. So no matter what algorithm you choose for dishing out the expired coin it could end up making mining ludicrously and socially destructively valuable compared to any other occupation. Even if there is a long delay from the point where the coin expires to when it shows up again that just moves around the point at which everything blows up.
In some ways your proposal as stated only removes uncertainty in that it makes sure the pessimal case _always_ happens: that after the currency deflates due to high usage, lost money appears out of the abyss and screws everyone up.
However, I don't think that "heartbeat it" _or lose it forever_ violates any of the system invariants in the way that "keep printing" as proposed explicitly by SgtSpike, and jon_smark. Nor does it create the possibility of a crazy gold rush appearing randomly in the future. (Heartbeating, incidentally would simply mean forming a new transaction, not an explicit heartbeat event.)
The obvious time to implement this would be at the same time as doing a cryptosystem upgrade, as the first expiration could be timed to adequately prevent a bunch of actually lost coins returning from the grave as ecc keys are cracked. It would be easily argued for then because people will easily see that the failure to implement it will allow the lost coins to return and blow the economy up.
I would expect the only debate at that point would be over if it should be a one time cutoff or a rolling one.