iOS 7 is a weird kind of flat. In many ways it lacks depth, but in others it’s more animated and texture-driven than iOS 6. How ever you want to define “flat,” it’s easy to see the direction Apple is headed. Just take a look at the details.
The magnifying glass in iOS 7 (the little orb that appears when you hover your finger over text) is minimalistic. iOS 6’s magnifying glass was more rounded, and the border was more pronounced. In iOS 7, it’s a nearly flat piece of glass. There’s some shadow to provide depth, but hardly any. Welcome to the future..