I get that the GNOME developers are trying to dumb down the user interface so that it does not confuse end users, and evidently developers and sysadmins are expected to use the command line or KDE for everything. (I in fact never want to leave Emacs.) However, the lack of informative error messages, as reported above, seems like it's going too far. At least put in enough info that we can search the Web on it. I expect there was some log I could have looked at regarding the GNOME Shell failure mentioned above, but what a pain, and how many logs would I have to peruse given that there was no hint as to the nature of the failure?
I would suggest that we have a different version of GNOME desktop for developers and sysadmins, one that has useful error messages and GUIs for system administration like we had in GNOME 2 (things that are now only accessible as system-config-* from the command line).