From wiki:
The aim of this mechanism is to make reliable payments to well-behaving masternodes. The alternative was to make the block payment to the last node which performed a DarkSend, however this would facilitate scripts in the nodes in which there would be a lot of bogus DarkSends just to increase one's chances to get the payment.
The main concern here is that a pool (statistically speaking, there are no miners and only pools..) gets some kind of say on which masternodes will get the payment. How much say do they get? It's important to clarify this point.
I was under the assumption it meant the system chooses masternodes that are up to date, online for a period of time and functioning well.