Choices are nice, but decisions have to be made on what code is justifiable to maintain just to provide an option. For example, the lack of Windows Classic theme in 8. That's simply not used by enough people to have the theme there, to have the .dlls, to have the resource files, or even as a fallback to more efficient operation. In Safe Mode, there is no such thing as a Classic mode because the WDDM driver architecture so vastly efficient over 7, there's no point in making Safe Mode to run the Classic theme.
Also, aesthetics. If you have noticed, the Xbox platform, Windows Phone, Bing, Outlook.com, Windows and everything else Microsoft is ditching the old Aero styling or xp era styling of gaudy push buttons and faux lighting and faux textures in lieu of modernist Bauhaus inspired design. Having Aero transparency or even Aero styling as an option in Windows 9 kind of throws a shiny, gradient drop shadowed wrench at that. They want to push a unified aesthetic that is digital and modern versus pushing your GPU just to show some eye candy. And continuing on that note, the target devices that will run Windows 9, like anything battery operated, needs to run as efficiently as possible. An example of that working is the HTC One M8 with Windows versus android. When the HTC One uses Windows Phone, the battery life lasts three hours longer than using android, a platform that pushes eye candy and everything opposite Windows Phone and more Windows vista.
Opinions and preferences are nice and all, we'd all love as many options as we'd like, but a line has to be drawn. Better efficiency and battery life trump pushing the GPU to just simply display the UI of the platform. And personally, I'd rather have an efficient desktop system than one using more power than necessary just to run the OS. I'd rather dedicated the remainder for Photoshop CC and GTA IV (YAY!) and other processor hungry programs.
But that's just me.
