Perhaps I was not as clear as I meant to be, but I think that iOS running on Mac hardware would look and function like MacOS. Finder, Dock, drag and drop, mouse support, etc. iOS has already shown with the Apple Watch that it can change its user interface based off the device it is running on. It functions and looks fundamentally differently on the AppleTV, iPhone, and Apple Watch, but at its core its iOS. I think that at Mac with an iOS core would be still driven and built around mouse and keyboard support, but application developers could recycle code from their iPhone apps much easier and hardware pushes forward like TouchID and Apple Pencil could be easily used on the Mac. I could even seen a scenario of a 12" Macbook with a Surfacebook-like removable screen that you could pop off and have the applications run in their iOS form. The iOS Launcher is already sort of on the Mac in the form of launchpad. I could see this scenario carrying over to the 12" iPad Pro as well, but in the opposite direction. It run like an iPad Pro until you attach a keyboard, have the iOS home screen disappear like Launchpad does on a Mac, and have a Mac dock pop up and the interface change itself when you have a touchpad/mouse and keyboard attached. I think if the core was iOS it would be easier for iOS to move up to do more Mac tasks and the Mac come down to meet iOS devices.