No way in hell Apple will ever allow anyone to 'theme' their iOS device, and with GREAT reason. I'm not sure if anyone has seen any of the jail break themes people have, but trust me when I say don't have any sharp objects around you, lest your eyes be gouged out by yourself. I've never seen a worse slaughtering of the beautiful iOS that comes on the beautiful iOS devices, it's a complete disgrace. It's absolutely no wonder to me why some people don't like how iOS 7 looks, and that of course is because their taste is among the worst of humankind. Go to the iOS 7 screenshots thread at the last few pages (since jail breaking has been available), and you'll see what I mean. It's actually impossible to describe how bad people's taste is. Every time I see someone say they hate iOS 7's look now, I just remember those themes and laugh.
It's no wonder they try to fix jailbreaks...if anyone saw those themes on an Apple device they would absolutely rather die than purchase one. I just wish I could send one of them to Apple executives and in particular Ive; they would probably laugh historically straight into crying their eyes out with the fact that someone had such a horrifyingly awful theme on their devices.