I don't have your IP, you don't have mine. The 3rd party in the middle does. There is a single point where all interaction with Slashdot can be intercepted.
I get what you are saying, but exposing IP addresses to 3rd parties isn't typically desirable.
What? That's exactly what you're advocating.
The flaw in the system is the central server.
Email works fine how it is, because of the requirement to store messages when recipients are offline. Yet it still doesn't suffer the problem of all messages going through a single entity. You're free to connect directly to the recipients mail server. You're not forced to go through a particular company or country.
Real time video links don't have that requirement. There is no need for a central server. All you need is some kind of directory. A DHT fills that requirement.