If you wouldn't care, you wouldn't hate it :)
It is not proven that Gnome3's or Unity's approach is perfect yet. However, the problems of the taskbar/windowlist is, that they are grouped by no order at all. Minimizing a window leaves no trail where to find it again, except the 0.3 second animation with shrinkboxes or some compiz effect. Users might remember that for some time, but not much.
Gnome 3's approach: When there is no way to minimize a window, it keeps its position. Keeping positions of objects is a powerful cognitive concept that Windows and KDE seem to have completely dismissed. And after pressing the funky key, users can see all the windows, not-overlapping, from a bird's-eye view and select much larger surfaces to access them. That is actually much more "efficient" that scanning a list of minimized windows that is arranged in a random order, or rather, in the order they happened to be opened.
Another good idea in Gnome3 is creating virtual desktops semantically instead of having a fixed number of them. So if a user is starting a new thing to work on, they can create a new desktop and fill it with the applications that they need for this task. This actually solves problems.
Removing many functions can be very "efficient", if efficiency is what "power users" are after, aka, doing things fast. Many great configuration options in for example KDE are totally pointless. I know I love changing stuff around a lot and have another checkbox to set some weird option, but since I changed to Gnome2.x, which was at the time laughed at for being dumbed down the same as Gnome3 is now, I am able to work much more, and more relaxed. My mind doesn't wander off by going through hundreds of tabbed config dialogs. I don't check the network traffic with an applet. I don't get a message popping up when a file finished being copied, along with a history of all file copy operations of the last month. Gnome is sparse. Which is great as long as it works well and you can be sure that the reason for a problem is not Gnome. In rich-option-environments, that, in addition, don't work well, you'll always feel anxious that some option you have changed might be the cause for the issue, and then try remembering which one that was.
Not directed against you, MrNiCeGUi: many people claiming to be "power users" and needing a lot of config options, are in fact wasting time and are just feeling to be productive by staring at pointless data diagrams or actually designing their own UI by moving stuff around, very likely making it measurably less efficient.
Hobbyists that love to fool around with their computers should be honest and say so, not stating "efficiency" as a reason. People who's job is to monitor computer activity, do maintenance or create work environments for others, might want and actually need loads of of options. But don't call that the peak of efficiency. It would for sure be more efficient if this work could be done with less configuration. In general, hating an interface without stating what it is used for, is quite useless.
BTW, iphone users also love their dumbed down touch interface because they feel more efficient with it. :) Of course a phone with a real keyboard is measurably more efficient, also the UI in my age old Palm Treo with PalmOS 5 can register dates and contact data much faster and more convenient than an iPhone. But it *feels* clunky because it looks like crap :) In the same way, powerusers might not feel like power users anymore when they have to do things that are commonly regarded as "consumer".