I like that idea of defensive driving course, mainly cause I had to do one (reluctantly) and it turned out to be the greatest fun ever.
Like our beloved 130 speed limit thing, states will only change the rules if there is something in it for them, ie $$$. So if said "crash body" wanted to seriously implement this, they'd have to start offering serious inducements to state, territory and federal governments before this would even start to become a reality. And not to worry about the revenue raising, people will still speed: when it's 40, speeders will do 60. When it's 60, speeders will do 80, and so on.
In my opinion, it's not the speed that needs to change, it's the education and mentality. Drivers should be aware of their cars capabilities, the effect of adverse road conditions and handling, the necessary maintenance for day to day running etc etc. And not through boring as lectures either, but real practical stuff, like the defensive driving, give people a real chance to learn these skills. If you had better trained, more aware drivers on the road, you wouldn't have quite as many easily avoidable accidents.
Dunno, just my opinion. I've got hundreds of them.