You do know that those "dummies" record all the forces in play during the crash, right? It gives the test engineers a realistic picture of how a human body would hold up in such a crash. The data they record during those incidents is very plentiful.

That is exactly what they're trying to determine -- Can your car "take one" for you?

And "skewed impact" -- well, they picked two of the most realistic types, which are offset frontal (it's unlikely you're going to hit a car square on in a "head-on collision" anyway), and side impact, to simulate what happens when you get schmucked going through an intersection.

You're right, though...crumple zones save lives, and that's why smaller cars can be at a disadvantage. There's little crumple before the high strength steel, which can put larger forces on the occupants inside.