Khoi Vinh:

Answering the question of how much to emulate desktop apps will likely take some time to sort out, but for me, it‘s self evident that the way we want to work on an iPad—even on a theoretical, professionally augmented iPad—is clearly not the same as the way we want to work on a Mac. Rather than providing full access to the work done on a desktop, especially when it can be as complicated as what desktop design apps produce, what’s needed is to give the user the most meaningful access, the subset that will yield the most productivity for designers working on the iPad, without all of the baggage of the desktop.

In Macs you can only have one cursor, in iPads you can have up to eleven fingers! Also keyboard shortcuts will be an unnecessary interaction model, because you can almost physically interact with your work on the screen.