I'm not asking Apple to create a 3rd aspect ratio or a 3rd resolution.
You may may have already realized it, but I'll break it down for you just in case:
1) Slice the 640 x 960 display into 5 rows. That means each row is about 640 x 192.
2) Now add an additional row into those 5 rows, so that means 6 rows at 640 x 192 each.
3) What do we get? 640 x 1152. Physical dimension considering 5 rows is 3.5" diagonal: 3.99" diagonal.
Why the analogy? Because the current iPhone's screen is exactly like that. The home screen has 5 rows of icon. With a 640 x 1152 display, it'll be exactly 6 rows. That's perfect scaling. You may also have noticed it, but the app switcher also takes up about 640 x 192.
It won't be a change in aspect ratio or resolution. I'd think Apple can still allow developers to develop for only 5 rows of that display (meaning the same 3:2 960x640 space with the same physical dimensions) and use the 6th row to display other information instead, like that virtual home button, or the app switcher, or Siri, or any other thing they please.
That's the justification for it. It's not a wish. It's a logical step up from the 3.5" screen because:
1) The aspect ratio would be closer to 16:9, so there will be less black bars, and more of a movie content can be shown on the screen.
2) It allows Apple to move away from double clicking the home button, or anything to do with the home button, even. Provided they want to do so, that is.
3) Since the scaling is linear, no change to any app currently would be necessary. All apps would work just fine, even those that depend on correct physical dimensioning. If any developer would like to use the extra screen space, I'm sure they may request to do so as well, and Apple will put something in to make sure the app won't break anything.
4) It's legitimately a bigger screen.
5) It allows more room to see things while you type in portrait.
While I'd agree that a 3.8" screen device would be better than a 3.5" screen, I don't think it'll happen because, again, it breaks many apps, that and it'll increase the dimensions of the device, potentially make the whole device heavier. That's counterintuitive to what Apple has been trying to do for years, and at least it'll make the iPod Touch heavier the way it is.
Other than that, the reason why I say that's wishful is because you are now asking Apple to physically change the dimensions of the device simply because you think that's what people want. For the record, again, that's what I want, too, but that's not a logical step-up because as I said, it would break one too many apps, and it confuses developers.
And I don't think anyone has ever claimed that the MacBook Air 11" was impossible. Apple has already created a PowerBook 12" before... so it's no surprise that they can make another one.
But it's not even the same argument. What I'm saying is basically that it's silly to think Apple would increase the MacBook Air 11.6" screen to, say... 12.1" because they have to physically make the MacBook Air larger, and that goes against their principles.
But as a matter of fact, the 12.1" MacBook Air idea is more feasible...