I'm interested in the fact that I'm approximately the only person I know who thinks IPv6 not a good idea, and that multi-level ("carrier grade") NAT is actually not just more likely in the short term, but better in the long term.[*]
I think our differences of opinion come down to this: most people seem to understand complexity differently than I do. As far as I'm concerned, building and testing two parallel systems (IPv4 and IPv6) is twice as much work. Testing a slightly more complex system (NAT) applied recursively (carrier grade NAT), requires pretty much the same level of testing as applying it only once. And we already test that because we have to.
Or, you know, I could just be wrong and everyone else could be right. :)
[*] We'll also want a good protocol for opening incoming ports through recursive NAT. NAT-PMP seems to be that.
ssh+2FA to all your machines, anywhere, without opening firewall ports.