I think the real problem is real-person identity management. Encrypted email is still a pain because we're still trying to shoehorn secure communication into a system that is fundamentally open and public, and filled with authorities that have to know something about you in order to route your messages to somewhere closer to your mailbox.
Email is still the text equivalent to the publicly switched telephone network. Domain names have to be registered. Mail routing has to be set up via DNS MX records and mail server software. It is like writing a letter on a postcard. Any attacker will be able to read the origin postmark, the destination address, and the ciphertext, no matter what code you use for the message.
All the problems with key exchange and trust chains is a result of trying to send secure messages from one known person to another known person. It's approaching from the wrong direction. People meet in person to grow their web of trust before exchanging secure messages online. But most of the people I communicate with online, I have never met in person, nor do I even know what they look like.
If I use secure pseudonym-to-pseudonym communication to set up an in-person meeting, and prove to the other that the human controls the pseudonymous identity, it should be impossible to determine how those two real people happened to show up in the same place at the same time. It should be indistinguishable from a coincidental encounter. You just can't do that with encrypted email.
I envision an uncountable number of large rocks, and masked ninjas running around hiding encrypted notes under them. The ninjas hang out in their darkened ninja bars, letting each other know which dead drop to use if they want to start a correspondence, and how to signal that it should be checked. But in the network, nothing exists unless someone runs the service, so all those rocks would have to be created and maintained by volunteers, and there is always the possibility that someone is preferentially using one of their own rocks, or setting up a fake rock to spy on anyone that lifts it.
I don't even know enough cryptography or spy tradecraft to even make a helpful suggestion on how to communicate with anyone on the network in such a way that all known attacks by state-level actors may be mitigated. All I can think of is the Black Hand missions of Oblivion (Elder Scrolls 4)--which used dead drops--and I ended up spoilering all the spoilers, because they had been spoilered. Never mind the philosophical implications of questioning how you even know whether a person you are talking to face-to-face, whom you have known for years, is really the person they appear to be. Do we even need to attach an identity to an actual face most of the time?