Scott Forstall played a major role in the Development of OSX - How can him leaving Apple be good??

From Wikipedia:

Forstall came over from NeXT when it was purchased by Apple in 1997 and is regarded as one of the original architects of the Mac OS X operating system as well as the Aqua user interface. He was promoted to Senior Director in January 2003.

In 2006 Forstall became responsible for Mac OS X releases after Avadis Tevanian stepped down as the company's Chief Software Technology Officer and before being named Senior Vice President of iPhone Software.

Wikipedia

He could have worked under Jony but leaving the Apple? We will see in time how that plays out.