Things should look like what they are. A computer display is not leather, so it should not look like leather. Making it look like leather is low-brow kitsch, like a fake electric fireplace or fake electric arc candles.
I hope Apple doesn't pursue the flat UI route a la Microsoft, not only is it not to my taste, but the use of subtle lighting effects have legitimate uses as cues to the user that an element is a button and can be pressed for example. Clearly this is not skeuomorphism as it's not a frivolous accessory but an aid for the user to understand the UI. This is not new either, buttons have been beveled since Mac OS 8 and Windows 3.0!
Essentially I think Apple will ditch the revolting skeuomorphism e.g. leather skinned apps, and continue to use subtle lighting effects and gradients to augment their UIs, and if they are truly planning a radical departure you can bet that it will be something rather original and not simply following Microsoft's lead. That is not Apple's DNA.
For non-touch and complicated UIs, it's a lot less useful. See Office 2013's mess of a UI, which also added ALL CAPS as a design element that literally conveys zero information (there's no common trait caps has across the applications, it's purely a random design change for the sake of some really poor design sensibilities).
I've been very hard on Flat UI in the past (and still dislike the overdone blocky look) but I've decided to embrace it after realizing it's true purpose.
It's NOT to destroy skeuomorphism. It's to destroy "forced focus design" in favor of "distraction free design". In the past we used gradients to aim the eyes towards a direction, shadows to make elements pop out of the page at a viewer, overly rounded corners to seem friendlier to the viewer, etc... We styled elements like this so we could draw attention to certain things and away from others. The same way people wear certain clothing to stand out or fade in with the crowd.
However, in this era of instant gratification online property owners not only realized that content is king but that there's too much shit to do and not enough time to do it. They need to give the viewer what they want and give it to as quickly as possible. Confusion breads negative feelings and pissed off viewers leave and don't return. So pages became lighter, more minimal, and lost unnecessary elements, and so designers adjusted to this.
By getting rid of the un-needed information on a page we no longer have to draw attention to one thing and away from the other because everything on the page is important. If it wasn't, it shouldn't be there in there in the first place. The buttons don't all need to have massive rounded corners and huge shadows because they're no longer lost in a sea of text and ads. They're easy to spot.
This is why you'll notice a lot of Flat UI sites are a lot more minimal than usual.
The Flat UI that I HATE is the blocky kind. Minecraft / 8-bit / designer out of college / what the hell's an a/b test inspired extreme flat ui. The kind where you don't know if that's a header with a colored background or a clickable button. The flat ui where everything on the site is so white white white you'd think the owners were clansman. That crap I hate. And it's only a few dozen A/B tests away from disappearing off of prominent sites.
I don't think this is "just a fad" anymore. There's a reason big companies are switching to it. Microsoft, Apple, Google. They're not stupid. They run A/B tests. They're not going to sacrifice market share, page views, usability, ease-of-use, and their bottom line just to blindly follow a design fad. That's just an insult to them. To say all Flat UI is backwards while the internet's biggest companies convert to it just goes to show how delusional and unknowledgeable we (especially I) can be. I apologize for my past remarks.
In other words, debates about "flat UI" vs "skeumorphism" (which is a false dichotomy imho, but I digress) should not be based upon things like "this era of instant gratification", it should be based upon how well the design serves the purpose of all design: effective and enjoyable use by humans.
The reason skeumorphism exists as an idea is not because it is used to draw the eye to something, it's to create affordances to the user by leveraging their past experiences. This can range anywhere from "this sticks out on the page and can be pushed" to "this reminds me of my real desk calendar."
Insofar as the Flat UI concept neglects to create these natural affordances it fails. The only argument one can make that draws upon the current status quo to defend it is if the world has moved on so fast that natural affordances created by depth and shadow can now be made just as effectively to most people by drawing a colored square instead. I'm skeptical that this is true, since three dimensional vision is pretty core to the human experience and human biology.
I think what we'll see from Apple will not be an abandonment of skeumorphism in general but instead (in typical Ives fashion) a distilling of it down to its core. Expect depth and shadow, but with a laser-like focus towards using it to create affordances instead of add unnecessary flare. Expect its use to be toned down both in prevalence and also in degree. The cliched example of the leather nav bar has never served any real purpose wrt affordances, so I don't think Apple will be clinging too tightly to it.
Keep in mind that your visual cortex responds more to difference in colours and spatial frequencies more so than it does to flat expanses of colour. Things like drop shadows and borders add much-needed high-frequency acutance  at the edges of shapes, which helps with object recognition.
You see this all the time in the real world - take a look at the logo on these cans  and note the white border surrounded by the black border. Going from the base colour like this, all the way to white and then back to black effectively saturates the spatial frequencies at the edge of the shape and forces it to stand out from the background - I'm holding one of these cans in my hand right now and boy oh boy does that logo ever pop.
You see the similar techniques around all the time - look at the text labels on Google Maps, or the black borders around video subtitles. Similarly, see the gradient and drop shadows on the icons on an iPhone home screen - those are there to make them visually recognisable as objects, as opposed to rounded rectangles.
Edit: further demonstrations of your visual cortex responding to differentials:
If you stare at the center cross long enough, your retina fatigues and the pink dots start to disappear. Likewise, the rotating absence of a dot is replaced by green.
The sharp spatial frequencies (unlike anything you would find in nature), aligned at right angles to one another interfere with one another so strongly that you start to see dots at the grid intersections (some may find this stronger than others, I sometimes get this effect from the Windows 8 homescreen, for chrissakes).
Metal or drop shadow or physical looking sliders imply solidity and weight. That was a desired thing in the era when we were getting used to screen interfaces. But metal implies that it doesn't move fast. You can't replace an interface with a new modal one that quickly or it looks unreal and weird, like you are flinging metal cabinetry around !
--after Apple declared it to be in style.
No, that's not what you meant, but it rings so true in the tech buzzosphere.
My decision is based on the new flat UI I've seen already working on Google's Gmail and YouTube properties as well as Microsoft's. They're not perfect but they're definitely heading in a better direction with flat ui. If I recall, Microsoft sort of started it with the Windows Metro look, then Google really sealed the deal by converting gmail and youtube into flat ui sites.
Here's metro influence gone awry:
It's pretty close to a flat look, but I still notice some subtle gradients going on. But talk about tile explosion!
I'd rather expect a toning down, a reduction – not banishment of gradients and all texture and personality. Look at the iOS 6 App Store redesign and iTunes 11 for visual hints.
Just as OS X toned toned the gloss and lost the pinstripes, iOS too will have its refinement.
Not Metro or Modern, the desktop.
Window titlebars have lost the peekaboo effect and use a solid color instead. The min/max/close buttons do a simple color change with a quick fade confined to their own little rectangle, instead of glowing around the edges. It's a subtle but pleasant improvement.
I don't like the Start screen, but not because of its flatness. It's the tiny text that doesn't obey my screen DPI setting and the gratuitous animation that really bothers my eyes. But that's OK, I use Start8 which brings back a non-animated start menu with the correct font size.
Welp, we're boned.
I hope this kind of innovation is maintained, because we the users benefit from this. In so many ways.
I wonder if Microsoft hadn't invested everything into flat design, would Apple had moved away from skeuomorphism so fast ? I think not. I hope to see Apple fighting for the design lead again.
My personal hope is that they push it a bit flatter than that to something like what Google did in their new iOS Maps app. We'll see.
The new interface is said to be “very, very flat,” according to one source. Another person said that the interface loses all signs of gloss, shine, and skeuomorphism seen across current and past versions of iOS. Another source framed the new OS as having a level of “flatness” approaching recent releases of Microsoft’s Windows Phone “Metro” UI.
So maybe I'm wrong. At the very least I expect it to keep the rounded corners instead of taking things to uniformly shaded boxes.
I think Steve Job might have come up with something different than Flat.
I have no idea and no opinion on which is better etc, just genuinely curious.
I guess it's possible that at some point the major interface methods will be standardized to such a degree that future changes will be aesthetic, to avoid putting off people, if nothing else. For instance, there was considerable resistance to MS changing the functional interface of Office not too long ago. But even mature consumer interfaces such as windowing systems continue to introduce additional functionality, although I guess some might characterize those changes as mere window dressing (heh), as well.
Some computer interfaces do head towards what some conceive to be the true answer, with a slow stream of incremental improvements, e.g. the Unix shell. But that's a professional interface subject to other kinds of pressures than consumer technology.
Hard creases are very in right now, as are sweeping contours (90s) -- today's style looks like 80s + 90s + modern facelifting.
I am envisioning if Apple does change to a flat UI look, it'll have their own little twist on it. I think it's a given they'll drop the skeuomorphism from iOS, because lets face it, skeuomorphic elements like leather books and note paper backgrounds look dated when used anywhere (not just mobile applications). I would expect things will get flatter, but evident by their latest Mac OS and iTunes redesigns which I think give us a sneak peek of the direction: not completely flat, still dabs of light & aluminium as well as rounded corners on things.
Whatever the end result is, I think we can all agree Apple needs to evolve. The iOS interface has remained basically untouched since 2007, it's time for a change because the aging operating system is starting to show its age.
No matter what happens in this scenario, Apple is left with two half interfaces. Not clean at all.
(I've certainly seen apps change behavior simply by being recompiled by a newer SDK, so there must be something in the binary loader that sets a bunch of compability flags or something)
Going purely by the strength of their design team, I'd expect iOS 7 to be closer to Android-flat rather than Metro-flat.
What extraordinary insight…
What goes around comes around.
That being said, there's no real reason why Apple has to use textures anywhere. Dieter Rams designed physical products which by their nature must have some texture or another. Having texture is purely optional in a digital product.
I'd also be very skeptical that Ive would create a sweeping change to a formula that works so well currently (Regardless of what the technorati think, joe consumer loves the iPhone UI. Small gizmos and refreshes are all that's needed to keep the standard consumer sufficiently happy), especially with Cook in charge.
A better article could probably be condensed into:
"According to sources it looks like Apple will follow the latest design trends and begin incorporating flat design into their products." Which is a no-brainer and hardly sells adspace.
Sigh... I miss the days of Windows 95? when I chose a theme and all apps had to follow it.
I wonder if Yahoo's new, aesthetically pleasing IMO, weather app is an indication of things to come to iOS.
That said, a complete UI overhaul is.. I just see it as unlikely all at once, more of a gradual thing.