For me, it's not so much that I want equivalency between the OS on the iPad (Pro or not) and the Mac. I would rather have parity, so far as that goes with the different UIs. For instance, why are some functions in OSX but not IOS? Keychain comes to mind. There are other functions / apps that seem to be fenced off, so as to preserve the east of use aspects (which I interpret to be dummy at the helm safeguards) in IOS. I get how the different UIs force the OSes to be different. But why can't the same level of functionality be in both other than that?