Frederico Viticci on iOS 9 - he's less concerned with bugs, and more concerned about increasing extensions. I'd like to see most of his wish list made, but I disagree with Viticci about the mission priority. I think it's easy for Apple nerds like us to make the assumption iOS is made for us. It's not - it's for normal people. There is no higher priority for Apple than to restore the public's faith in their software.
Engineering is about priorities. You can't do everything, especially on a yearly release schedule like iOS.