A lot rests on the head of iOS 7. Since its inception in 2007, iOS has retained basically the same UI, with minor graphical tweaks as the hardware became available that could support the added flourishes. Other operating systems, like Android and Windows Phone, have popped up and started challenging the iPhone's dominance, both in marketshare and design. According to the WSJ, Apple isn't planning many drastic changes in iOS 7, which will possibly put a slight damper on the iPhone 5S' launch.
If Apple were to update the look and feel of iOS, however, they should turn to Jesse Head, a graphic designer from Australia. Head has designed, and produced a mock-up for, a new UI for Apple's app switching mechanism. The mock-up includes a new "tile" interface, similar to that of Windows Phone and WebOS, which allows the user to jump quickly between apps in a beautiful, fluid way. In the included video, head demos a number of proposed changes, including a new way of interacting with open apps. Like WebOS, apps can be swiped off the page to close them, a neat feature. The new app switcher also would allow the user to search open apps quickly, something many iOS users wish for.
Whether Apple will unveil anything dramatic in iOS 7 (and we're hoping they do), is yet to be seen. But if they want any advice on how iOS should be done, they need to hire Jesse Head.