Defenses of Gnome 3 rooted in explanations of its alleged technical excellence are irrelevant to users, who can make the only judgement about it that matters. Users never see technical quality unless it is so bad that it breaks something. They see capabilities and ease of use. I am stymied to understand how Gnome 3 adds capabilities and increases ease of use.
Gnome 3 has a panel I cannot use. Whatever happens in that panel happens outside my control. It is little more than a narrow band of black paint across the top of my screen.
At the bottom of the screen is a large "Notification Area". That is a misnomer because its primary use is to house icons representing the kind of things Gnome 2 called applets. In fact, the Notification Area remains unseen when Notifications pop up. On the other hand, the presence of the mouse cursor will un-hide the entire Notification Area, even if contains only a single icon. The effect is remarkably like a Gnome 2 panel set to autohide.
The thing that passes for a dock in Gnome 3 is merely an over-large stack of unalterable icons. It is as if the Gnome 2 code that handled favorites in a panel was edited into a vertical stack fixed to the left edge of the screen. with the size of the icons increased to a size comfortable for finger stabbing. I do not stab at my monitor, so their unalterable size is very much a negative.
Some have derided Gnome for allegedly copying portions of OS X's interface. That is not justified because the OS X interface is much more usable than the Gnome 3 interface. For example, the Launch Pad in OS X can be entirely ignored by a user with no decrease in capabilities. The Gnome 3 version of that Apple mistake, called the Application Overview, provides the *sole* access to applications offered by Gnome. It cannot be ignored.
Gnome 3 has, in fact, been subject to much criticism that amounts to little more than Gnome 2 nostalgia. However, it has also received a very large amount of justifiable criticism from people who, like me, find it a disappointingly annoying interface in actual daily use that provides no positive counterweights to the increased amount of work a user must do to accomplish basic desktop tasks.