I was under the impression that NAT was regarded as a "bad thing" on IPv6
It's a "bad thing" on IPv4 as well. The problem is that so many people have never seen the efforts that have gone into working around the breakage it causes, haven't seen the countless piles of cash that (for example) VoIP providers have had to invest in proxy machines to work around how NAT breaks SIP. Not even good old FTP works without help from an ALG in the NAT gateway.
Besides, with "home" routers coming with uPNP turned on by default, your security from NAT is (while not completely useless) severely compromised since ANY device on your network can ask the router "please open wide these inbound ports for me" and get them.
So in response to the printer comment, all it takes is for ANY internal device to fake a uPNP request from the printer to the router and the printer can be accessible from the outside.
There may be things that make IPv6 "difficult" - not using NAT isn't one of them.