If we have the limit at 250DRK, the person with 1000DRK will just have four "tickets" instead of 1. So the outcome is the same really, with the same security too.
The only difference between 250DRK and 1000DRK is that we'll end up with lower end master nodes. I think we need only people that really understand security, ddos protection and how to run a service with 99.9999% uptime. These nodes are going to be the life blood of the whole network, so those things are highly valuable.
I agree in principle, I'm just not sure I understand how a higher cost of entry ensures those things.
A higher cost of investment and a lot of money as risk will ensure the person at least understands what he's doing.
Later on I envision we'll have master node pools where you can buy shares and receive a percentage of the payout. This will offer smaller investors the same investment, with someone else managing the node that can protect it.