Read this article on Forbes
http://www.forbes.com/sites/berlinschoolofcreativeleadership/2013/10/15/interview-designer-david-yun-on-the-pros-and-cons-of-apples-ios-7/
David Yun thinks Apple made some big mistakes with iOS 7 from a design / usability perspective and also from a brand perspective.
“It has a lot less to do with the design community and more to do with the constant drive to sell new products,” Yun explained. “That said, the intention of iOS 7 is completely valid. It’s the execution and the qualities of that execution that are in question. Here’s hoping for a closer look at those qualities in iOS 7.1!”
If Dieter Rams the legendary designer at Braun (which is Jony Ive's inspiration and hero) had something bad to say about the design of iOS 7 I'd understand. Looking at David Yun's work I'd hardly call him a guru. It seems like he just wants a little attention.