In pitching iOS 7, Apple makes note of the fact that the revamped mobile operating system relies on "cinematic animations" and "new approaches to animation and motion to make even the simplest tasks more engaging". Most would agree with the sentiment, but not a number of people with certain conditions who've flocked to Apple's Support forums to complain how iOS 7 makes their life difficult.
Motion sickness stems from iOS 7's heavy focus on parallax and zooming effects. Regardless of where you stand, it's a very real problem. Now, Apple does provide a very limited control in Settings to somewhat reduce motion in iOS 7, but people demand the firm take a more proactive approach and design granular controls to help alleviate motion sickness...