Re: "nat-has-nothing-to-do-with-security"
The thing is, your problem isn't the IPv6 protocol but rather the greater Internet itself. Your problem IOW isn't in L3 but in L2, and you need to address your issues there with things like physical proxy servers that provide a physical layer of separation. Internally, your choice of protocol is up to you and irrelevant here. Externally, you may want to find a way to talk to IPV6 destinations before you get shut out, but by your standard that a problem for your gateway to solve. You don't HAVE to keep end-to-end connectivity if you don't want to, but it's better far to have the option open and not use it instead of not having the option when you need it.
Biting the hand that feeds IT
