The problem is simple, there’s no hierarchy, they were more concerned with making a “pretty” Mondrian design than creating a logical eye path.
More frequently used icons should be more obvious and more easily utilized, and the more ancillary, secondary icons should be segregated by size, location, or visual “level” as far as reduced contrast or some other visual organizational structure.
The “desktop” metaphor has grown, improved and evolved over the past thirty years or so into a very workable graphical user interface. Websites use it, larger touchscreens use it, even television uses it and it’s typically not even interactive.
Scale is the only reason to move away from it, as in smartphones and tablets. Even then there are much stronger visual differentiations between icons.
Windows 8 manages somehow to be both flat and a visual assault at the same time. Lack of hierarchy and visual differentiation of apps and functions is the reason why, it’s too large on devices with large screens.
The whole idea of totally matching interfaces across all media is only being put forth by Microsoft and it’s not an accurate representation of how the different devices are used anyway. Tone it down on the PC desktop, admit that no style points were won, it just confused their core customers.
You misunderstand ...
I don’t find a jumbled mess to be particularly simple.
Metro is a jumbled mess.
If you like it, bully for you. I’m not interested.
I use a computer for rather more than reading email, browsing the wwweb, and looking at pictures, and I have been doing so since the late 1970s.
ALL operating systems suck.