Been busy lately working through some design considerations for iOS7. I can't get into great detail about the inner workings of the updates, but overall the design process is radically different for the latest version of iOS. The above image is a small glimpse of what I'm thinking about designing for the next Dice Tracker update (which will be iOS7 centric)
I think the biggest change is the visual impact that iOS7 apps have. I am curious to see how many developers follow suit and change their apps to match the latest style, but I'm guessing a lot of big apps may retain design guidelines of versions past. The minimalist UI works well for some experiences, but the lack of texture and visual direction (for example, the lack of borders around buttons) is going to be a major challenge for apps that target broad audiences.
Let me be clear though, I don't think iOS7 will fail. I'm just not sure if that style will be applied as broadly as Apple was hoping it would.
Thankfully, the update is not skin deep. Apple has added lots of new APIs, and lots of new features are now available to developers that were not available before. It's an exciting time indeed.