I would freaking love it if some good designer with technical knowledge, or help from technical colleagues, would create simple flowcharts of "How to use Encryption".
Each chart would be one page. It would walk a user through one step of using a PGP / GPG. It would include links to in-depth reading.
The final sheet would be walking through common mistakes that users make.
This is one of the things I'd pay for if I had FU money. I'm sort of tempted to kickstart the idea.
It's not doable, because there are major unsolved problems. Protection of a private key, for example.
The only outcome of such a chart would be reams of people utterly vulnerable and thinking that they are not.
If you constrain the environment, e.g. "How to use SSL certificates in Chrome on Mac OS X Lion" then there might be a chance that could fit on one page in an easy to understand format.
I have a master key that was created offline, and use a subkey on a usb smart token. It works good but it was a bitch to set up. Apparently Qubes OS has a hardware-virtualized PGP container for protecting private keys, but that's not a viable solution right now.
The offline masterkey stored on an encrypted medium is the approach that makes most sense. This[1] guide is pretty decent, and somewhere on the Debian wiki is essentially the same information (but less nicely presented).
The OP's complaints boil down to two IMO: 1) poor UX; 2) trust is difficult to manage.
1) Seems solvable to me again with subkeys for encryption and signing (which I believe are created by default for GPG2.0 anyway).
2) Asking technology to solve the problem which only each individual can answer ("do I trust this person to be evaluate other people's identities as carefully as me?") is not doable.
The example of someone getting a journalist's pubkey and being stung by the (fixed) bug whereby the wrong key may be imported is again letting the user off the hook. If someone is not actually using GnuPG's abilities to examine the WoT and see who has signed the journalist's key etc then it's an example of magical thinking with "encryption" replacing any other nostrum.
I don't believe that problem can be solved with technology.
Each chart would be one page. It would walk a user through one step of using a PGP / GPG. It would include links to in-depth reading.
The final sheet would be walking through common mistakes that users make.
This is one of the things I'd pay for if I had FU money. I'm sort of tempted to kickstart the idea.