Pros and Cons of Flat Design

I found this insightful: "[flat design] can hinder usability because users don’t always know what is clickable."

I ran into this playing with iOS 7 beta. When I'm trying to close an application in their new overlay, I expect to "tap out" of that mode. It didn't work. Turns out I had to swipe it away, and I think that would have been more obvious without a flat design.

Or, straight from the master: http://www.nngroup.com/articles/tablet-usability/