Really, Microsoft has just made a good argument for Apple to release a larger (and even thinner) iPad Pro sometime sooner than later â€” that actually sounds great.
The Microsoft Surface Pro 3 sports a 12-inch 3:2 (1.5:1) display. The iPads are all 4:3 (1.33:1). If an iPad Pro were to grow in size to 12 inches I think it might be too wide (in portrait mode), but I also don’t think Apple would change the aspect ratio. Usability for a 12-inch 4:3 iPad Pro might be less than ideal.