NAT = PBX
Come to think of it, that's two attacks on the concept of Network Address Translation in one day.
NAT seems to me to be the networking equivalent of a PBX. When you work at a large company, you probably don't have your own phone number - someone calls the main number, and then asks the receptionist (be it human or computer) for your extension, or looks you up by name.
The problem is that right now, NAT works more like a company where there is no receptionist. Folks inside the company can call out, but nobody outside can call anyone inside the company.
Of course, in the real world, I can't call someone up and take over their bodies and turn them into zombies that will start calling other people and taking them over.. This would be the real world equivalent of the sorts of worms that exist on computer networks. That's why you can't just ask the router to connect to an internal computer, unless someone has explicitly configured it that way.
I don't think we're likely to find a better solution than the one we have today. Putting every PC back on the Internet would definitely be a bad idea; why are smart people proposing this?