To me, the smarter solution would have been for Apple to position unoptimized apps not in the center, but rather flush to the bottom. (I'm no artist, but you can see my rendering of what that might look like in the image atop this article. The actual approach is on the left; my alternative is on the right.)

There are, of course, advantages and disadvantages to this approach. On the plus side, every element of the app would remain the same distance from the bottom of the phone as it was on previous iPhones: The tab bar would remain on the bottom, and the top of the app would remain precisely the length your thumb learned to stretch over your past years of iPhone usage. Scrolling through a lengthier email or article, you could run your thumb right on the bottom edge of the screen as you always did before, with no fear of hitting Gruber's "dead zone."

One big downside to this approach: it wouldn't work well at all in landscape mode, where I think the centered, letterboxed solution makes more sense. It would be odd to see the screen jump as you rotated your device.

But I bet Apple's bigger concern would be the gaping black space that would be left at the top of the screen if apps stayed anchored to the bottom. Personally, I think we'd get used to that unused black space pretty quickly--but that doesn't mesh very well with Apple's desire for the market to embrace the larger screen. If using older apps felt okay with that big black gap at the top, some developers would likely feel considerably less motivated to update their apps; Apple would prefer that developers keep up with its hardware changes.