To be clear, the double-height status bar changes the "aspect ratio" of the device. On WebOS, they have a really great notifications mechanism that involves slowly making the screen smaller (up to a point) as more messages need to be rendered. This is the kind of feature that Apple should be allowed to implement without causing havoc on existing applications, and would cause even more drastic disturbances in aspect ratio.

Also, on other platforms, there was at some point "the one monitor" that came with the system: the fact that so far we've only had two different aspect ratios on iOS devices (3:2 and 4:3) is no reason to believe that the next device won't be something more like 16:9. There is no reason that most applications couldn't be designed to be ready for such a seemingly minor change.