Windows 8's user interface has been completely revamped with the addition of the Metro style, and even the standard desktop mode was tweaked to offer more functionality. Now, developers have announced that the upcoming version will lack a prestigious feature: Aero.
The Aero glass interface was introduced in 2003 as a direct consequence of competition and of course, user feedback, Microsoft wishing to catch up with the translucency effects which could have been found at the time in Mac OS X. The effect basically added transparency to certain elements, such as windows and panels.
In the latest Building Windows 8 blog, Steven Sinofsky spoke about the brief history of the Windows UI and what concepts will the upcoming version tackle. Although there were no chapters specifically made for this announcement, Steven stated that Microsoft is "moving beyond Aero" for design reasons.
It seems that Microsoft wishes to drop all transparency and reflection concepts, by going towards a simpler, crisper design of the windows and taskbar. For instance, the default colour for all windows is now white, all rounded edges are now squared and the appearance of a wide range of buttons, boxes, sliders and even the Ribbon has been updated.
All of these changes will not be seen in the upcoming Windows 8 Release Preview and will be introduced only in later builds.
Source: Building Windows 8