I don't know about Jony leaving the headquarters... I know morphing designs are going to be important in the future, but right now iOS hasn't even hit 3D icons that Linux had with cairodock... We're gonna have a bad time. Just look at windows 10... Barely getting aero back... And nobody told them we wanted 8 to be that flat. Maybe Apple should develop a feedback app for public beta testers and devs like windows 10 has so they don't screw up majorly.
That is your opinion. About the only complaint you have is they did something different from what already existed and you didn't like it.
The flat interface was a brilliant move bringing those that whom could not connect to the skeuomorphic elements of the iOS 6 and previous designs. Once you get outside of western culture, the UI elements of iOS 6 and before were not intuitive to non-western users since they had no cultural connection to the metaphors presented.
A good example of this is the flat logos describing different sports in the Olympics since the 1970's. Before then, the Olympics were mostly a western cultural event. By the 1970's it truly became international with most second and third world countries participating. These new logos stripped out western metaphors to communicate the sheer utility of the sports.
The "flat" interface of iOS 7 and on brought out the sheer functionality of the iOS to users. Now that non-western market is assimilated, we are seeing some more depth in these interfaces.