Yeah, calculation of the amount of possible strings containing only a-f is trivial. But the idea is for addresses to be memorable. So I'm wondering how many strings which are valid IPv6 addresses are possible if you are limited to actual English (or, pick a language) 4-letter words containing only a-f. As someone mentioned, this could be expanded with 1337-speak.

You don’t need a NAT with IPv6, that’s what link-local addressing is for

With IPv6 for most use cases there's actually more security. With privacy extensions (pretty sure it's enabled on windows by default), when you make connections from your device, it uses a "private" IP. That is a randomly chosen address inside your network's prefix, that changes regularly.

These addresses don't accept incoming connections. You have a main address that doesn't really change that you accept connections on. Firewall that for ports you want to allow and then hackers need to port scan 2^64 or 2^80 address space to find your real IPs in your prefix. If they capture your IP from a connection to a web server etc, they won't have luck scanning you.

Again as per my post above, the biggest risk right now is bad default configurations on many home routers.

exactly, I also like this peace of mind for my home network and see no benefit in using ipv6 there. Similarly for any VPC I deploy to an IaaS.

I like that none of my local devices are externally addressable unless an outgoing connection has been established.

This can also be achieved using (other) firewall rules.

but then it's essentially just maintaining a NAT table without the translation piece.

So... a firewall?

NAT isn't a security feature and shouldn't be relied on for managing access to hosts.

It also breaks the assumption of IP that connections between hosts are end-to-end, which requires sophisticated solutions so that everything works (more or less).

I too employ NAT to make services accessible over IPv4. But only because it doesn't work otherwise. Not because it "makes sense". I don't use it at all for IPv6.