GNOME Shell -the UI revolution is well under way

[...]but for us mere mortals, Facebook, Gmail, iPhones and Android have radically changed what we expect from our UIs

I'm a mere mortal and I cannot stress how wrong this assumption is. I expect my UI to give me access to my stuff in the least amount of actions. Pure Gnome 3 Shell is not delivering that (mouse, view switch, mouse, etc.). Shell with MGSE (Thank You Linux Mint!) does, although it still is a step back from Gnome 2.

Where we used to open a file manager and navigate to folder with ten files, we now have our data online.

I doubt this is the truth. Maybe a few have jumped into the Cloud, but the majority have their files (legally obtained or not) on their harddrives. Where are the reports that the sales of MS Office have plummeted dramatically, because everybody and his dog is now using Google docs? It might be true that a subset of the computing populace puts the minutiae of their uninteresting lives on Facebook, but to do that they didn't need a completely wrecked desktop experience. The browser was and is interface enough for the destruction of personal privacy.

Bringing these concepts to the desktop just makes sense.

No it doesn't. A desktop OS is not an extension of the Internet. The Internet is just a network between desktops and servers. I personally don't need a "Me menu". Chat in my corner of the world is dead, so I don't see a need for an integrated chat solution. Facebook and Hyves have all but killed one on one communication via chat programs. It is all unidirectional publication now. Read what others think makes them look cool in the world.

And sharing files is something which should be as seamless as possible.

The RIAA, MPAA, BUMA, BREIN, STEMRA, BAF, BSA and a lot of other X letter agencies beg to differ.

While Xfce might offer a familiar interface, it doesn’t offer the most efficient UI any more.

Says who? Why did Linux Mint get so much acclaim for bringing back the menu, panel and window list to Gnome Shell? XFCE at least changes incrementally and so far only for the better.

As a final note I should stress that I don’t think change for the sake of it is good. If reality changes, however, you have to be prepared to change with it.

Well, call me a stick in the mud, but I've not seen any desktop computers change into MID's overnight and worse than that, I don't see Gnome 3 and KDE Plasma Active One or Unity making any inroads on these new fangled, mobile computing devices. Build it and they will come, doesn't work here. It will take active pushing to get it there and I don't see the pushing.

The long-term net result should be high productivity with a short-term hump in the road as we get accustomed to these new ways.

A tablet interface on a non-tablet machine is not increasing productivity. Putting tractor wheels on a city car doesn't make a new workhorse. The only major desktop that didn't go insane is KDE. They still have a traditional desktop for a traditional desktop machine. It's just too bad that the pain of the KDE 4.0 rewrite lasted a few years, before they were back with a usable DE.

Gnome 3 Shell and Unity are of their rocker. The sooner they fall to Earth, the better. The base technology in Gnome 3 is sound, it's just that the takes on the "desktop" metaphor from the Gnome team and Canonical is wacky.