IPv6 was a lot more than a numbering scheme, there are performance (and security?) improvements in a number of aspects of IP networking, like more compression in parts of the messages IIRC.
Gonna have to disagree with that. IPv6 was designed in the 90s and lots of it feels like it is. Icmpv6 is fundamental to the implementation and already responsible for multiple remotely exploitable vulnerabilities. Couple that with almost no one understanding it well besides a true handful of engineers and you have yourself a security nightmare. Proof of this is this very thread with the talk about “trying a local link address”.
Everything about v6 is over engineered with sharp edges.
