Perhaps there are two disagreements here:

1.  Is a mildly-inflating currency better or worse than a fixed-supply currency?

2.  It is possible to inflate a currency without having to trust a central planner?

The answer to #2 is "YES".  If you modify bitcoin to have a constant % block reward then what you get is a forever-inflating currency.  But if this were the case, we would also know for a fact that the freshly-printed money would go entirely to garbage output (miners will simply consume electricity [natural resources] faster than is required to secure the network).  

So, to have any hope of not wasting the extra money inflation, you must argue that the central planner is not only wiser than the free-market, but vastly wiser to turn a net waste into a net gain.  This is a tenable position in my opinion, and I think the answer to #1 is "WORSE."


Hmm, maybe we can put this into a theorem.  Still half-baked, but here's a start:

Peter R's Theorem on Monetary Inflation for Fully-Adopted Currencies

Money created by a trustless currency by way of inflation goes entirely to exploiting natural resources.  

Corollary #1

An inflating currency that is not provably inferior to its fixed-supply equivalent requires trust in a central planner.

Corollary #2

An inflating currency is superior to its fixed-supply equivalent if and only if the unproveable efficiencies made possible by the wisdom of the central planners outweighs the loss of monetary freedom that placing trust in central planners entails.