There is one aspect for which iOS 7 could be called "flat" - there's a lack of gradient shading. There's little attempt to make the UI elements (icons, controls, views, etc.) look like they are physical objects with 3D depth via artificial shadows.
You might also call the iOS 7 design philosophy "borderless." The delete button is now red text that says "Delete." The weather app now just presents the weather, rather than putting a border around it as if it's a physical card that must be fit within the screen dimensions. That's not consistent throughout the UI though - there are still button elements that have borders around them (in Control Center for example.)
I'm thinking this might be an mistake on Apple's part. In the WWDC presentation on their new design, they talk about how they mimicked physical objects because that's what people are used to handling via their fingers. People intuitively knew how to operate the iPhone because it mimicked how they interacted with real-world objects. In the WWDC presentation, they said that they no longer need to do that because people are now familiar with how to interact with digital objects, and they no longer need the physical object cues. That's true for most of the current iOS users but it's not true for everybody. One of the things that made iOS so great to use is you could pick it up and start using it right away, without having to read a manual. Back in 2007, compared to the alternatives available, it was a mind-blowing experience to use an iPhone. Even today, you could give it to somebody who had never used a computer and they could understand it well enough to get around. But now? With Apple deliberately removing those queues because "we" know how to use digital devices? I dunno. It's hard to put myself into the shoes of somebody who's never used a computer, plus I haven't used iOS 7 personally, but I wonder if they'd have a difficult time getting things done - which, I suspect, will hurt Apple's sales of iOS devices.
But then, maybe Apple has worked in some hints to our intuition on how to operate the OS. I dunno. Time will tell.
You might also call the iOS 7 design philosophy "borderless." The delete button is now red text that says "Delete." The weather app now just presents the weather, rather than putting a border around it as if it's a physical card that must be fit within the screen dimensions. That's not consistent throughout the UI though - there are still button elements that have borders around them (in Control Center for example.)
I'm thinking this might be an mistake on Apple's part. In the WWDC presentation on their new design, they talk about how they mimicked physical objects because that's what people are used to handling via their fingers. People intuitively knew how to operate the iPhone because it mimicked how they interacted with real-world objects. In the WWDC presentation, they said that they no longer need to do that because people are now familiar with how to interact with digital objects, and they no longer need the physical object cues. That's true for most of the current iOS users but it's not true for everybody. One of the things that made iOS so great to use is you could pick it up and start using it right away, without having to read a manual. Back in 2007, compared to the alternatives available, it was a mind-blowing experience to use an iPhone. Even today, you could give it to somebody who had never used a computer and they could understand it well enough to get around. But now? With Apple deliberately removing those queues because "we" know how to use digital devices? I dunno. It's hard to put myself into the shoes of somebody who's never used a computer, plus I haven't used iOS 7 personally, but I wonder if they'd have a difficult time getting things done - which, I suspect, will hurt Apple's sales of iOS devices.
But then, maybe Apple has worked in some hints to our intuition on how to operate the OS. I dunno. Time will tell.
