@Uwe Dippel RE "Virtualisation is one thing"
Microsoft are of course recompling Office to run on ARM and yes you will likely have to interact with it by means of keyboard and mouse. Tell me, are you seriously saying that you would wish, for example, to type a long Word document using a virtual keyboard? I personally think that for a lot of people being able to interact as they wish with the os (whether it is by "prodding" it, or keyboard/mouse combination or, yes, even taking notes with a stylus) dependent upon what they want to do may turn out to be a good solution. I certainly think that there are enough of our fellow earthlings who are capable of chewing gum and walking straight at the same time for them to be willing/happy "to learn two different interfaces for the same application." where they have reason to wish to interact with the app concerned in more than one way. It is also in the nature of the "form and function" equation that there will likely always be apps where the one or the other way of interacting with it will be better/more natural for the individual user.