I think apple was smart with the way they went mobile, in that they didn't really try to carry over any of their exiting OSX UI. Often it is 10x harder to unlearn habits than to form new ones. If I'm presented with something that is 'exactly like before except for a bunch of glaring omissions and additions' it will feel like the uncanny valley and getting used to things will be much harder. Apple went for the 'Everything that you do in iOS is new but seamlessly intuitive' route which lends a reasonable learning curve and more importantly no steep 'unlearning' curve.