I don't find it very inefficient. There's also plenty of customization. This is a pretty specious comparison; on iOS you literally pay money a la carte for minor customization options. On GNOME, you might have to turn to less-supported third party extensions, or God forbid do some very minor config file or command line work. Far less than you'd need to do to do something similar in a tiling wm, of course... And most things that end users who just want to actually use their computer might care about are supported already. The system tray is the single feature I think is glaringly missing from GNOME currently, hopefully they'll get that officially supported soon.

Kind of weird to get so bent out of shape about some people choosing to use a certain interface.