The difference in safety is significant: a child riding rear-facing is five times safer. Another way of stating this (taken from this site) is:
In 100 collisions of rear facing kids, 8 rear facing children will die or become seriously injured. 92 will walk away fine. In 100 collisions with forward facing kids, 40 will die or become seriously injured. 60 will walk away fine. Those are large differences which help to save lives.
Nate and I laugh about our society's over-protectiveness; Nate once joking that "in the future, all toys will be colorful plastic wiffle-spheres". Certainly turning all toys into "safe" but bland objects would have an impact of kids' development, and they'd surely find more interesting (and dangerous) things to play with. We can't eliminate all the risks. Based on the statistics, though, I don't think that keeping your child rear-facing for 2 years or more is excessively overprotective, or that anything in their development will be sacrificed for the increased safety.
Today's families seem to be putting on more miles at higher speeds than previous generations, and it is good to know that we can keep reducing the number of serious injuries and fatalities that occur.
If you have children or will soon, and your car situation allows it (our pickup truck is not very conducive to rear-facing, so Tobias does face forwards in the truck now), I strongly encourage you to research and follow these recommendations.