A few weeks ago I read about how some the new dynamic user interface features of iOS 7 were causing motion sickness for some people. Frankly, I wasn't surprised. I found that some of the transitions, particularly the zooming of the app startup and going back to the springboard, too flashy. It demos well, but you get tired of it quickly.
Apple had apparently considered this to be a potential problem since they included a "Reduce Motion" option in Settings/General/Acessibility. But the initial implementation of the "Reduce Motion" option only addressed some of the problem. It turned off the parallax effects but not other motions such as the zooming.
Well, Apple listened and the iOS 7.0.3 update more aggressively tones down the motion. No more zooming in and out of the springboard. Instead you get a nice fade transition when going from springboard to app and vice versa.
So if the excessive motion was preventing you from using iOS 7, give the latest update a try.