[dpark]

> Besides, when each app takes up all available real estate, do you really need consistency between apps?

Yes. Consistency between apps is what allows you to start up a new app and intuitively know how to use it. You shouldn't have to re-learn how to interact with each app.

> Distinctive styles are just a nice reminder of what app you're in.

Distinctive style up to a point is useful and pleasant. Gratuitous differences make interaction more awkward. Even at the purely aesthetic level, a reasonable level of consistency improves the feel of the device. When an app looks completely different from all the apps that come with the device, it looks less distinctive and more out-of-place.