When DRK hits $100 a masternode will be worth 100,000 bucks
Who will risk running such a server besides security geniuses?
You can have your 1000 DRK in a "local" wallet running on your personal computer and have the server running the master node with an empty wallet. So even if your public server is hacked, they can't steal your 1000 DRK.
will future masternodes require less DRK?
No - dev said that 1000 DRK is a good number, any lower and there will be too many nodes causing too much network load.