Wouldn't this be something that remains steady over time? It will add to the block size, but it will not increase over time.
We will have a limited number of allowed masternodes.
(Well, I still advocate that Mr. Spread lets the number of masternodes slowly grow over time, something like (Available coins)/1000.
I think this is important to always be able to attract newcomers, and not give the impression of "the club of the 1000 MN owners",
this would be wrong IMHO. )