Thanks for all of the replies. It seems the overwhelming opinion is to make the swap. I would like to just point out one other thing that has been brought up and wanted to clear things up. For the last year or so we've already made the Leaf our primary family car. Whenever we go somewhere in the evenings or weekends we take the Leaf. Even if my wife goes out shopping or whatever in the evening, she takes the Leaf. This is primarily because of the mileage issue. We have had many discussions about our differences in how a car is kept. So she is well aware of my opinions. She does tend to give my car more respect than her own when she drives it because she knows I'll be upset if she does not. However, I have caught her eating and drinking in the car before on more than one occasion. She has spilled Dr.Pepper in her own car on many occasions, fortunately the Volt has leather seats so it cleans off. The carpet is more difficult. Fortunately she has never spilled anything in the Leaf (that I know of).
Now, having said that... There is another issue to consider. Since the Leaf is our primary family car and also my car then that means when the family goes out together we are driving a clean car. However, if we make the swap then the Leaf will still be our family car but will now be trashed. So at that point when we go out as a family we'd be riding in the "trash mobile" as I like to call it.
We have not yet made a decision on this. We're still talking about it.