Much of the discussion of iOS 7 has been little more than criticism of the icon design. As Gartner analyst Brian Prentice points out, for developers the appearance of individual elements matters far less than the overall app experience.
As Prentice notes, changes in the surface appearance of the built-in iOS apps aren't matched with fundamental experience changes:
When I search for clues in Apple’s own apps, the feeling I get is that the upholstery on the furniture has changed, but the room’s purpose and layout is the same as it always was. Adding depth as a new dimension to app design seems to me to have profound long term potential. But if it’s primarily demonstrated at the top level of the operating system by floating icons above your wallpaper, then we have something which will rapidly descend into ho-hum ornamentation.
It's not purely an Apple issue — Microsoft faces similar challenges with its Modern interface. The whole post is worth a read