Everyone has their own metaphor for the changes that Apple has recently brought to iOS 7. Using the beta on my everyday iPhone since the keynote, there is no doubt it feels very different to iOS 6 and in some very specific but tricky to describe ways.
The new layers and depth, the 3D parallax effect and the flat unadorned, untextured surfaces throughout instantly make me think of the first videogames with proper 3D graphics.
It's interesting to juxtapose the evolution of iOS -- perhaps the first OS whose visual and interaction design started with a clean slate and enough GPU power to make graphical interactions the core of its experience -- with the evolution of videogames from sprites and bitmaps to polygons and textures.
Consider Street Fighter II. A classic fighting game played on a 2D plane. All the visual depth and detail comes from the artwork itself. The background is drawn such that the floor looks like it's receding backwards and the fighters themselves get their solidity in the same way, through highlights and shadows that give their muscles definition and the cloth of their karate-gi's weight.
Similarly, iOS 1 uses gradients, drop shadows and the signature glossy icon crescent to bring its interface to life and provide the illusion of depth.
As technology improved, so did graphical fidelity. For videogames, this meant higher resolution graphics, more detail and sharper images. I'm cheating slightly by using a very modern Street Fighter II screenshot (for screenshot comparison consistency), but you get the idea.
And for iOS 6, the same applies. Everything about the interaction design remains identical, but the level of detail is cranked up even higher. There is detailed visual work everywhere. Drop shadows, inner glows, gradients, gloss, textures, faux wood, leather, plastic, glass and steel, the works.
Then one day, on a trip to my local arcade, I saw something completely new: Virtua Fighter. The first ever 3D fighting game sacrificed a lot of visual detail in order to achieve real depth rendered via multiple polygons on a projected z-axis.
When I first saw Virtua Fighter I was not impressed. The graphics were terrible compared to my favourite at the time, the also just released Mortal Kombat II, but it was the start of a new era that still continues today: the vast majority of new videogames are first or third-person perspective 3D.
The marketing told the story very clearly:
This game has an extra dimension. The quality of Virtua Fighter's static graphics didn't matter -- it was about how the game felt in motion -- rather different to the 2D fighting games that came before, even though the vast majority of the combat still took place in a single plane. The illusion of depth wasn't just painted on anymore, it was fully modelled and shaded and the player could move into it.
With iOS 7 the same holds true: the action takes place on a flat screen, but the feeling of 'real' depth is there too.
When you look at a static iOS 7 screenshot, all you can see is some simplified icons and a notable absence of drop shadows.
In use though, the new transitions, animations and physics combine to have a noticeable impact on how navigating the OS actually feels.
Regardless of what you think of the new visual design -- personally I think they've gone a little too far in removing button affordances -- I would urge you to wait until you've used iOS 7 before you judge the new interaction model as a whole. Watching the attract mode of Virtua Fighter wasn't enough to judge it accurately either.
So what does this mean for the future? Presumably that iOS 11 will require the Oculus Rift to experience it fully. Maybe Google is on to something with Glass after all.