I've experienced problems with my Toyota but it was because the cruise control sucks. When the car starts losing speed (caused by hill or headwind), the cruise control doesn't slowly apply gas until it gets back to the set point. Oh no. It downshifts and races the engine hard until the car is at least 5 MPH past the set point. So much for fuel economy. And I can see how this would cause an unprepared driver to freak out and make things worse.
I haven't seen signs of bad engineering, just sloppy engineering or cheaping out. I also have a problem with any car company who's saying, "We're perfect, it's our drivers who are stupider than average."