Of course this is a real issue, and I'm not at all surprised it exists, given how psychedelic things look even in some of Apple's press photos. Visually induced motion sickness (VIMS) and visual stress (http://www.lucid-research.com/visualstress.htm) have become very active fields of research because of the implications in applications ranging from (FPS) video games to jet and airline pilot training through alleviating reading problems in dyslexics and enjoying contemporary art. And it happens to be one of my fields of research.
What IS surprising is that Apple neither foresaw it nor identified the issue from beta tester feedback (or worse, failed to take that seriously). I can understand an industrial designer like Ive more used to working on physical objects could be unaware of the effects visual displays can have on people, especially if they move, but surely he must have had computer graphics experts in his team...
This is a health issue comparable to epileptic attacks caused by certain kinds of flicker, first observed on a large scale because of a now infamous episode on Japanese TV. I think it's serious enough for Apple to provide EITHER a very rapid update that allows to disable animations or reduce their duration significantly (something I think should be configurable anyway, at least after an initial hour or so of having "admired" them ...) OR a well documented way to downgrade back to 6.1x (and sign that release again, of course).
In the meantime, the symptoms are aggravated by certain kinds of colour contrast. Without going into too much detail, it ought to help to select a very drab (grayish or with a slight tint of a colour you perceive as soothing) background, to reduce brightness and/or contrast, turn off the parallax bling and experiment with inverse video mode. These symptoms are accumulated, meaning each obnoxious stimulus will aggravate matters, and so anything you can do to reduce/remove them will be beneficial. That also means that "just don't look" when those animations happen should be a reasonable avoidance strategy ... and if indeed it is, it might be the perfect argument to convince Apple that their eye "candy" really is as bad as classical candy is for the teeth.
I presume that previous iOS generations were not or much less affected by VIMS because of the soothing and largely monochrome appearance of the glass GUI...