The problem with the robots is that there are so many aspects where you can tune. For example for the lower parts of your test piece, a different tool geometry would help a lot, but in turn would cause problems further up. Then the position of the 3D print within the robot's workspace makes a big difference, and of course also the orientation of the tool within the constraints of the physical process.
A dedicated software could have some optimization strategy ready to help, but KUKA|prc is used for countless applications, each with different parameters, so that is more up to the user. That being said, at least for prototypes, intuitive interaction with the parametric object is often faster than setting up an optimization process - that is one of the strengths of GH as a platform, in my opinion.