Zod, and your perplexion gets the foundation that the Start Menu folder structure is still there. And every screen-element's color registry values are still there - like they have been since Win95-B. So full user customization via the UI would be possible IF ONLY they'd left the "Advanced" button on "Window Color and Appearance" dialogs available.
Users have had this split-personality choice between 'themes' before - since XP, in fact - stay Classic and familiar, go Aero (or whatever). Of course, Aero was soooo cute and glitzy, but NOW Microsoft has been saying, "It's soooo resource hungry and we're rather leave Power To The User-People." As long as the people are treated to a Siberian Gulag Re-Education Program. Gee - any wonder why the masses aren't boarding those Ballmer-Express railroad cars?
Actually, there seems to be a push to castrate all Classic features - Start Menu folder structure, registry values - and force us into a WinStore-Apps Start Screen mode only, where purchasing and constant tracking-of-user-and-their-apps can be done under the guise of greater security. There's that hardened kernel again, too!
This all seems like another one of Basil Fawlty's Business College lessons: "I could run this place so well if it wasn't for customers!"