Unfortunately, that does not provide a solution. Since public IP addresses are becomming scarcer, and since at least one side needs a global address, all of the workarounds for NAT will tend to centralize the 3rd party coordination/proxy role.

Even IPv6, which should provide direct addressability in the long term (assuming ISPs provide it on the wire), may wind up increasing the centralization in the short term (creating a single point of failure and censorship) if the only way to connect to the IPv6 Internet is to tunnel into a major tunnel broker; rather than hundreds of ISPs, there may only be a handful - easy targets for mandatory kill-switches, censorship, and surveillance - and what started with more addresses than stars in the universe, will have degenerated into a global hub-and-spoke network.