This is a little unclear. You made a very clear and concise explanation of why you thought Supercoin had problems.
Now, however, it seems that you were not aware of how XC's trustless system works, and may have dismissed it prematurely.. Though I am happy to be corrected, but I can't see how you could have if you thought the previous poster meant "every node on the network".
I would be very interested to hear your thoughts on XC as you have a good understanding of these issues, and are fairly measured, and if Cloak and Super do indeed have problems then it may be that XC is the coin which could provide a better solution than Crypto Note coins.
Thanks in advance
Contextually the conversation was around trustless systems - my comment was meant to demonstrate that you can't have a trustless system unless "everyone" is or could be involved. If you require an N-sized subset of the network to validate, then it means you are trusting that nobody in the subset group are malicious. It was quite late and was an unclear comment, unfortunately.
Incidentally, I keep coming back to a simple premise: we need to see valid mathematics behind things in order to understand them. These discussions wouldn't happen if whitepapers had more algebra and fewer "diagrams" (such as they are). The knee-jerk reaction here seems to be "just look at the blockchain!" or similar, when looking at the blockchain created by a closed-source application won't reveal the size of the anonymity set. Bitcoin assumes that all (bar 1) connected peers are malicious (it can do nothing about complete isolation), and that should be the basis from which all good cryptography starts. A lot of the "solutions" I see lately start from the assumption that "every peer is basically ok/trustworthy and has no incentive to be malicious", which is patently wrong.