This all sounds wonderful but I still think they’re a bad idea and shouldn’t ship enabled by default. The problem isn’t that they’re not handy (zing), rather that they break what I feel is one of the key wonders of iPad — it becomes the application that is running. These multitasking gestures add a set of interactions that relate not to what is on the screen but to an abstract higher-level of functionality. The touch screen is now an input into two systems: the application and the operating system. Despite the utility I believe this is a step backwards and certainly a trade off I’d be hesitant to make so early in what will undoubtedly be a long-lived product’s life cycle.
His idea of using the Home button seems unwieldy, but I agree that it makes sense for system-level gestures to require something more than touching the screen.