Essentially, user experience requirements for 10-inch devices are one thing, smart phone design another, while seven-inch tablets present a third platform that has to be designed for distinctly from either full-screen or smart phone apps.
"Re-purposed designs from print, mobile phones, 10-inch tablets, or desktop PCs will fail, because they offer a terrible user experience," he says. "A seven-inch tablet is a sufficiently different form factor that it must be treated as a new platform."
On one hand, seven-inch devices do not support easy, pleasant, and efficient use of the broad range of user interfaces optimized for other form factors. In other words, seven-inch screens are too small to easily browse full websites, and yet too big to carry with you at all times like a mobile phone.
On the other hand, they are capable enough to provide good usability when designs are optimized for the platform. The screen is large enough to show pictures and full-color illustrations, and it can also support fairly efficient navigation and other user actions, he argues.