Most of the IPv4 stuff that ISPs are already using today was either never designed for the NAT444 subscriber model, or if it was, then it's badly broken and not as well engineered as the comparatively older and better designed IPv6 stuff. This is especially apparent when you're looking at service providers with more than 16 million subscribers, who need to number subscribers in multiple separate address realms. This is the main problem cited to me by operators who have rejected NAT444 in favor of IPv6 DS/DS-lite.
For evidence, I don't have much to point out except the fact that every major ISP in the United States and Europe, and many in Asia as well, having looked at the operational considerations associated with the NAT444 and IPv6 DS/DS-lite alternatives, now seems to have concluded that the latter is superior to the former. Admittedly, I have nothing but anecdotes to relay if you want help explaining their observed behavior.
As for making GoldenShield workalikes, yes Virginia— that's a piece of cake with IPv6. Easier, actually, because you have only a single address realm to manage.