Sorry to hear that you are unhappy and you will probably disagree with me, but for me “Expert Mode” means people that read documentation and don’t just explore. And for such experts like yourself I think the command line will always be the best tool. As any expert GUI is just an abstraction added above the command line and I think it’s a bit of a trap to design a GUI for such experts.
During Key generation I do not want to make users think (too much) as they will then automatically think it’s to complicated and run away. And for a User that does not know about OpenPGP UserID’s its just an unclear question if the GUI asks: “Do you have a comment on this?” I’m actually unhappy about the “Subkey settings” advanced GUI of the Key generation dialog.
FWIW. I also agree with most of what DKG wrote. It’s not that users can’t be trusted but it is hard to think of a usecase for comments especially regarding certification. If I want to Certify your key I would also have to certify the comment. And while I can clearly check your Name, or the email address you use. How can I verify that a key with a comment like “offline key” is really your offline key?