I LOVE the idea of NAT-less global internet. It's why I love IPv6. At that level anything that wants to participate should be secure and "go Chrome" for leading the charge. I even think firewalls for global IPv6 are stupid. If you're global you're global no amount of silly packet filtering rules is gonna change that.
But that's not the end all. I don't want my entire house to stop working because I got a new ISP and I have a few days of down time. Or more like because my ISP went down because they oversell bandwidth and haven't updated their routing hardware in 15 years. Maybe I don't want my file server with all my family photos globally addressable. Maybe I don't want my kids on the global internet at certain times. The point is I know what's best for my house. Im sick of the old IPv4 mindset where the only reasonable model is centralized global trust (see we agree that's been the status quo).
Most people have no clue about computer security and don't want to get one. Tomorrow's grandmas will know as little about how their computers are attacked as today's grandmas.
And they don't want to know. They want technology that is safe to use.
We know from experience that a network where devices trust each other is a disaster waiting to happen. So let's kill that model. All devices have to survive in the open internet. Because if they don't, somebody will figure a way to attack them.