I was never sold on the idea of swipe becoming pervasive. That being said, I'm not sure if a 'natural feeling' interaction for the sake of convenience is necessarily the best.

The swipe interaction isn't the most intuitive interaction for new users navigating around screens or other digital content and Apple seems to have used it for content that's derived itself from physical content or pages, such as books or images. If Apple were to use swipes as OS wide navigational gestures, it would preclude the use of swipes in app-specific contexts