Any system which relies on trivial input can be easily gamed. I (and other merchants) could buy/rent enough hashing power to solve 1% of blocks and fill them with massive fees (which come right back to us) and inflate the average fee per block.
Hmm...This was a problem in my first idea but I fixed it for the last two. Do you an exploitable problem with the
most recent proposal?
I would point out that a fixed money supply and static inflation curve is non-optimal. In theory a central bank should be able to do a better job. By matching the growth of the money supply to economic growth (or contraction) prices never need to rise or fall (in aggregate).
I disagree. There's nothing particularly attractive about fixed prices. Especially troublesome is when growth in the money supply is politically directed (versus doled out through proof of work). But this heads us in the direction of "deflationary currency" debate so I'll stop here.
...you propose that the size will only increase but never decrease? Anyway, the major problem is the choice of total reward amount because change in purchasing power is unpredictable.
Yes, size would only increase. If we allow the size to decrease then it could cause fees to skyrocket. I proposed
a new scheme that does not depend on total reward amount, I believe it addresses your concerns.