I made these mockups weeks ago to see what a black theme would look like. I think it looks pretty cool on the black phones, and yes, all the white doesn't look so good and the black phones. However, with a black phone, I don't think the mainly white UI is a problem when you're using it. When I use the device, I'm just looking at the screen, so it doesn't feel weird. I think iOS7 on the black phone is far less presentable in pictures because in pictures, you take in the whole image. In
use, I think it's fine. Although maybe offering a black theme would help it not be so bright when you don't want it to be, and with the way iOS7 is designed, it would be incredibly easy for Apple to allow this. I think having a black theme like this feels a lot less inviting, and far more intimidating, so I don't see it happening. Nonetheless, here are the mockups:
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