IPv6 is in most ways simpler than IPv4. There are a couple of gotchas but honestly all you really need to do to see this look at the IPv4 and IPv6 packet header structures to see that they difference is minimal and IPv6 has less room for complexity. You lose NAT (it is possible but nobody really does it), your TTL is now just a hop count, the netmasks are more or less like the old IPv4 class networks instead of the classless setup we use today. Each network gets a minimum of /64 (that is 4 billion squared addresses), and you actually have proper and functional link local networking.
But yes it uses colons instead of dots. Sorry about that.
I set up IPv6 at home and realized every single device in my house got a globally routable IP by default and was confused for a second.
Oh! This is how the Internet was supposed to be!
Remember, we only even bother with NAT bullshit in the first place because there aren't enough IPv4 addresses.
The difference between "has a routable IP" and "this should be routed" is exactly the problem for 99% of the population.
I'm not saying NAT is a good thing but at least it's one more thing from preventing network shares of everyone's pictures on shodan. I'm also not saying it's a good protection, but it's not zero.
Maybe if ipv6 had been the default since the beginning, then OSes and default configs would have been written in a better way.
I really don't see why we wouldn't end up in a world where home routers had a firewall by default and the user (or their agents) would open up ports as necessary.
Still like NAT, but better.