We probably won't ever be rid of NAT. The likes of Cisco, who thrive on making things enterprisey and needlessly complicated will definitely be peddling IPv6 NAT soon, if they aren't already doing it.
You're probably right, but many telecoms have already deployed ipv6 without a bunch of layers of networking hell, and I'm hopeful that they'll just junk all the crazy ipv4 stuff without replicating it in ipv6. It'll be cheaper for them and nobody will notice the difference.
NAT gives the same amount of security as dropping all SYN packets at the firewall level. The latter just requires much fewer resources to do as it allows for completely stateless operation.
IPv6 NAT is generally discouraged and providers can gain huge benefits too from not doing NAT. NAT always implies state which needs to be stored somewhere. The moment you NAT, you very likely won't be able to do the routing in pure hardware any more, so throughput is an issue.
routing v6 directly is completely stateless. It can easily be done completely in hardware possibly not even requiring to store the packet anywhere, nor needing any knowledge of the protocols wrapped inside of the IP packet.
To do NAT, you need to know about TCP and UDP and about the various ports which means you need to look into the IP packet. To route v6, you just look at the IP packet.
