"So, Tony Stark gets to choose: disclose the details of the invention in a patent and correspondingly get superior civil (i.e. monetary) relief if someone copies it, or try to keep the invention secret himself and hope that criminal law dissuades people from stealing it."

This implies something that isn't true: that Tony Stark has to choose between the two strategies. In reality, he could choose to patent parts of the Iron Man suit and keep other parts trade secrets. As we software developers well know, you are allowed to patent each individual innovation, not just the whole of a product.

For example, Stark Industries could get multiple patents on the suit software. They could get separate utility patents on the thrusters, the briefcase fold-up design, and some of the suit-specific weapons. Additionally, they'd try to get design patents on each of the suit designs. But, they could still keep the power generation unit and the navigation software secret.