They are safer. How much safer? I'd have to go read up and find whatever official documents exist.
That said, how many Caravan's have you seen in the ditch? I've seen relatively few. IMO vehicle stability control (VSC) is important on trucks/SUV's, or perhaps more properly, more important for those top-heavy vehicles. Is it helpful on other cars? Sure. Critical? Myself, I am not shopping on the basis of that. I'm content with airbags, ABS and crumple zones.
I wouldn't trade out of an '05 just because of lack of VSC. Lack of ABS, age, high miles, general distrust of vehicle, or general dislike of vehicle, sure. But I think VSC is chasing diminishing returns in terms of safety.
But that's just my opinion.