As someone who uses a Linux desktop at work essentially non-stop the great thing about the "old" GNOME 2.x interface was how powerful the keyboard access was. The HI Guidelines did a fine job of making sure I only needed to touch my mouse for certain positioning operations and object selections in a few apps. Navigation through the system didn't need me to move my fingers away from the keyboard.
To date, though I'm still practicing, I can barely launch applications from the keyboard. It used to be [Alt]+[F1]+[arrow keys through categorized menus]. Now it seems to be [Alt]+[F1]+[guess the name of the application]. I can't seem to browse categories the way I used to.
Tabbing now seems to be between applications rather than between windows in an application so I have to reach for the mouse to select a window. I never needed the mouse to select a window before. Am I missing something?
There used to be a geometric layout of desktops. I bound semantics to my layout for really fast mental switching. Now there is only a growable, linear list of desktops. How is this linearity an improvement? (If you are interested my approach is to have two rows. The upper row is for running applications and the lower row is for support activity: browser windows at docs, terminals set for screen capture etc. Each column - and I have six on the fly by default - is for a separate activity.)
The comments on touch suggest to be that the designers of GNOME 3 have fixated on a single user group: the light-weight occasional user. They seem to have screwed the heavyweight user in the process, though.
Note that there's a lot of "seems" in the text above. Another annoying shortcoming of GNOME 3 is the lack of documentation about keyboard shortcuts. Is there a definitive list of all of them anywhere? I searched the GNOME website but came up empty. Perhaps "keyboard" is the wrong term to use.