Before we jump into the comparisons, let's examine a few constants and key decisions that Apple has made which make the direction iOS 7 has taken a necessity.
1. Apple hardware revisions come only once every two years.
As a hardware manufacturer, Apple has been phenomenally successful. This is due in large part to their strategy of offering very few devices to a particular segment of the market with significantly higher margins than their competitors. Furthermore, they typically only make significant changes to these hardware designs every two years which reduces costs and increases profit margins.
This choice limits their flexibility in terms of responding to new market demands, especially in the realm of device hardware features. Luckily for Apple, over the past six years they have essentially been defining the gold standard by which other players in the market must compete. This has allowed them to maintain high margins and their perceived position as innovation leaders with a best-of-breed product. Attempts by competitors like Samsung to add differentiating features to their handsets and tablets have for the more part failed to attract any significant traction (see Samsung's 'S Beam'), perhaps with the notable exception of screen size...
2. Apple refuses to compete with other devices on screen size.
Screen size has been the one feature that Apple has consistently chosen not to engage the market in competition on. While Samsung and others have grown to beautiful 5" displays, Apple remains steadfastly committed to their 4" screen. This comes back to the key belief of form over function that has guided Apple's philosophy over the past 30 years. A bigger screen makes for a wider device that simply feels too big for your hand, and many feel looks silly held up to your head. Ever tried one-handed operation of a Galaxy S4?
This decision means that every single pixel on Apple's display must be absolutely optimized to present as much usable screen real-estate as possible on the smaller screen, so that apps can compete with the larger displays available with Android and others.
3. Form over function still rules.
Apple has thrived on its ability to look different, feel different and be different. Leading the charge on this front has been the enigmatic Jony Ive. Now Jony's talents have been squarely focused on the software, as opposed to hardware, and the effects could not be felt any more strongly than what we've seen in iOS7. Jony and Apple have always been supremely focused on building beautiful things, where material and form meet to provide an elegant and superior user experience. The guiding principle from a hardware perspective has always been 'simplicity'. No unnecessary buttons, features, labels, or keyboard keys ('Delete' anyone?).
With Jony driving software design, it should have been no surprise to see the direction iOS 7 has taken...
The bottom line: No more room for Skeuomorphism
Jony has taken this consistent approach to completely revamp iOS, reversing course on key design approaches, primarily by killing skeuomorphism in iOS. Skeuomorphism is defined as the rendering of real-world concepts and interfaces in software in an effort to give users a familiar set of real-world analogies. Think of the leather binding in the previous iOS 6 calendar app.
At the end of the day, the death of skeuomorphism in iOS is simply a practical matter vs. a philosophical one. There's just no space for it. Skeuomorphism requires pixels be committed to rendering the real-world looking buttons, textures and backgrounds. Simply put, the 4" display cannot afford it.
iOS 7 is stripped down to the bare essentials, and that's just the way it needs to be.
Apple's continued commitment to a smaller 4" display requires the elimination of skeuomorphism which commits far too many pixels on the screen to rendering life-like analogies in all of our apps, especially Notes, Calendar and iBooks.
With Apple hardware that is locked for 24 month revision cycles, it is software that must respond to the market challenges that continue to rise from the increasingly competitive Samsung, LG and ZTE. Love it or hate it, iOS 7 is that attempt, and expect to see continued advancement in that direction.
While rumors continue to circulate that Apple is testing larger displays for it's handsets, the fact remains that a larger display would almost inevitably adversely affect the 'form' of the device which fits nicely into one-hand in it's current dimensions. We will have to wait and see how Tim and his team decide to respond to, or lead, the market with the next revision of the ever-so popular iPhone.
UPDATE: Bonus video from a good mate of mine showing the reaction of a young iOS user to the new iOS 7 interface...