Jakob Nielsen has written a column about Windows 8's usability, and he pretty much nails the major issues.
On the topic of the vestigial Desktop:
Unfortunately, having two environments on a single device is a prescription for usability problems.
This is probably the biggest issue with Windows 8, and, while playing around with the OS, the one that bothered me the most. Microsoft should have just killed the Desktop, and perhaps allowed people who really needed it to download a traditional file manager from its Store.
On window management:
When users can't view several windows simultaneously, they must keep information from one window in short-term memory while they activate another window. This is problematic for two reasons. First, human short-term memory is notoriously weak, and second, the very task of having to manipulate a windowâ€”instead of simply glancing at one that's already openâ€”further taxes the user's cognitive resources.
While Windows 8 supports showing two windows at the same time, the UI for it is undiscoverable, and, worse, confusing once discovered.
On the iconography:
Icons are flat, monochromatic, and coarsely simplified.
I actually think that the flat, simplified icons are a good idea. I was never a big fan of the detailed 3D rendered icons used in modern systems. These plainer icons make for a much simpler and more easily recognizeable iconography. However, the lack of color is inexcusable.
The tiles suffer from a similar issue, but for a different reason: they are so dynamic that it's hard to figure out what exactly you're looking at. Windows Phone's tiles are mostly icons, with some dynamic, colorful tiles mixed in. This works well. On Windows 8, on the other hand, many of the tiles start out showing an icon, but eventually display dynamic images, which ends up being confusing and overwhelming. Or they just show text, and forego iconography altogether.
Much of Windows 8 just lacks polish. For example, turning a tablet running Windows 8 doesn't rotate the screen; it just jumps from one orientation to the other. It's just a tiny detail, but one that can be disconcerting when actually using Windows 8.
In general, I think Windows 8 is a step in the right direction. It makes sense to combine tablets and notebooks into a single class of computers that run a single operating system.1 Unfortunately, it's a bit of a stumbling half-step. Much of it is poorly executed; many of the UI mistakes seem unprovoked, and should have been avoidable.
I found it surprising how quickly I got used to the touchscreen on a Samsung Series 5 I was using. While I was typing, I'd use the trackpad; when my hands were off the keyboard, it felt very natural to just touch the screen to get it to do what I wanted. ↩︎
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