End users won't tend to notice this change in any way that they'll connect with what they see on the desktop, though it has made some interface changes easier. They also make it easier for quick navigation of a fairly complex environment. Even though the panel, for instance, was easily configured and arranged on the desktop, there was an underlying sense that it was best to stick with the default configuration. Second, there's a level of confusion with regard to e-mail support. There's more to it than that, though.
Any environment has to justify the overhead it imposes on a system.
There's a lot of flexibility present in terms of how the panels are placed on the screen. The panel is also resizeable down to a mere 24 pixels in height, making it much less intrusive than the default 64 pixels. In fact, after a short time, we had whittled the default bottom panel down to screen-lock, logout, and screenshot tool buttons. All of these individual pieces hang together well, providing a largely consistent interface. Happily, that should be changing.