I am starting to see a trend of GUI being structure-less / hierarchy-less. A prime example is amazon's Music App for windows. It moves from screen to screen with no apparent logic, with some screens (like the download manager tab) appearing sometimes but with no obvious way to get back to it if we hide it. Same thing for the itunes app which doesn't show on a screen how we got to it. Both seem to be inspired from the web, except that the web pretty much always has a menu at the top which gives a good idea of where we are.

The Windows 10 UI also seems to follow this logic and seems to have ditched the idea to show any apparent hierarchy in the sub menus of the control panels. Particularly in full screen mode.

I can't tell if it is because I am used to deal with GUIs that have a clear hierarchy that this design upsets me, or if it is simply because it is badly designed. I guess the acid test is whether a kid can find his way comfortably.