I do have to admit that its pretty impressive that they are able to stand up to a DDOS attack by adjusting mining settings.
That is because it is not "DDOS", but an *internal* difficulty, inherent to the way it functions ; in other words, a bad billing scheme for computation, such that expensive computation was billed way too cheaply, making it possible to launch a lot of computation for a small price, something the nodes couldn't handle. In other words, ethereum nodes were overselling their capacity of computation, and someone took them on their word.
All this is *inherent* to the concept of ethereum. Yes, one can mitigate, adjust, try to protect, .... but on a Turing-complete system, one can never solve this issue for good.