It isn't bad engineering when you look at it from an OEM stock point of view.
When left as designed and built, it is excellent engineering. It was designed to be light, strong and simple.
The biggest problem is that when an enthusiast wants to use headers, they find that the factory didn't leave any room for them.
Why should they? What possible advantages are there for a car manufacturer to engineer their cars so that the 2% of owners will have an easier time to modify them?
I love headers. I use them on my performance cars so this is not an argument against them.
Look at the design. Rear mounted steering gear is less susceptible to damage and allows the steering column to be shorter. It also moves weight toward the center instead of further forward. Torsion bar suspension allows for lighter control arms and for the weight to be lower and more toward the center.