And also, dos attack sounds highly inefficient because even if you'd get all the other nodes out, the data you're grabbing with your own nodes will mostly be uninteresting to you, and the trail will end very soon because the funds are constantly being anonymized. A script which monitors your node's status and launches a new node on a different service operator if needed could also be developed.
I don't know whether masternode owners turning against each other is plausible, as that kind of activity would affect the coin valuation negatively, so I doubt the incentive is there, but we'll see.
I don't really understand what's the problem with 1. is though. People use different addresses for different purposes. Those who don't, won't risk other users unless I'm misunderstanding something.
Well no, if you read about the 2nd part you would see that DDOS-ing 1000 MNs isn't even that hard. Well i'm interested if one of them has some input on the matter. As for this:
Outputs can still be linked to addresses. If you send 20 DRK and it sends all these other outputs along with it to obfuscate, the 20 DRK still ends up in someone's address. That this can be observed on the blockchain means that analysis is easy, and we all know how often people leak addresses associated with their wallet (eg. posting it up for giveaways etc. etc.) This is an immutable problem in any Bitcoin-forked cryptocurrency that exists, as the solution (stealth addresses computed w/random data) has to be enforced for every transaction from the genesis block. If you enforce it halfway through you're stuck with old outputs that don't use stealth addresses, which makes it exceedingly complex to ensure the anonymityset is not at-risk.
DRK has enforced it halfway is what he was trying to say. He said that these are just his concerns. I would like to watch a discussion between him and our developers, that would be interesting.
You can try and DDoS my masternodes, which have DDoS protection - If that fails, I will just get new IP addressess allocated or switch providers within an hour or two. This has no effect on anonymity as majority of users will have pre-denominated funds sitting in their wallets ready to spend.