I used to get car sick as a kid. I haven't felt queasy from motion in over a decade. IOS 7 was the first thing that brought that feeling back. I think the problem isn't so much with motion as it is with the unnatural motions. You move the tablet, and the background only shifts a moment later. You rotate the tablet, and the rotation of the screen isn't smooth but jerky. IOS is very tactile. In IOS 6, I felt like I was moving things around. In IOS 7, the lag and jerkiness make it feel somehow wrong.
Either way, I suspect Apple will either want to release an update which gets rid of the lagginess and jerkiness, allow the user to disable animations, or face an ADA class-action lawsuit.
If they do plan to fix this, I wish they'd go against convention, and pre-announce it. I need to know whether I should replace the iPad with a Nexus 10 (something I've been considering regardless; I have a Nexus 4, which is wonderful; but hasn't been worth the $$$).
Somehow, the Surface, which has much the same feel as the IOS 7 in terms of being a little bit slow, laggy, and occasionally stalling out, doesn't suffer this fate.
(I have an iPad 3; and iPad 4 is twice as fast, so perhaps it doesn't suffer from this problem).