Can't tell whether this is trolling or serious. Breaking the end-to-end principle has had profound effects on the Internet as a whole for the last 2 decades, centralization being the most obvious one.

I used to keep a copy of this paper with me: <https://web.mit.edu/Saltzer/www/publications/endtoend/endtoe...>

Citation needed on "breaking privacy". You have at least 2^64 IPv6 addresses per household, cycle through them and stop worrying about IP tracking.

Oh, and I can give citation on how NAT breaks something. Until the day we can magically remove application-level gateways[0] I consider NAT a fundamentally broken hack.

[0]: https://en.wikipedia.org/wiki/Application-level_gateway

That's not how any of this works.

I can't tell if this is sarcasm or another "I like NAT because I can't be bothered to deploy a firewall rule" comment.

I said nothing about a firewall. I use firewalls everywhere. I use NAT. What I don't use is IPv6.