From the few i-MiEV crashes we've seen on the net, the car does hold up pretty well in a wreck. There's also the small size of the i-MiEV creating a nimble car that can avoid most collisions better than larger vehicles. It also has some of the best brakes I've ever experienced in a vehicle. Regen alone can quickly bring the speed down, but couple that together with front discs, a low center of gravity, and near 50/50 weight distribution, you have a car that can go from 30 mph to 0 in 15 feet. In the winter, losing control on snow is actually a challenge (at least it was for me).
If you are set on trading it, what are you looking to get out of it, and where are you located? I know somebody that really wants one.
In an effort to stay on topic, though, last September my light came on. I called the dealer, set up an appointment to check it out, and it was a bad impact sensor. They reset the light while it was there and it came back mid-October after charging in the rain, though I doubt it was charging related. In December, the part came in and they changed it out. Haven't seen the light since, though I still get a little shock when I glance down and it's on when I start the car (it's the last light to go out on startup).
