Making block space arbitrary scarce will subsidies miners at the expense of people who are using the network for transactions. If the network security is the ultimate goal then it will be better to have indefinite inflation of fixed or variable amount of bitcoins per block because it will tax everyone equally not only those who are trying to make a use of the system by performing transactions.

My personal opinion is that free market in most cases works better then any arbitrary economic rule, therefore I am against subsidizing miners with more bitcoins then absolutely necessary.