Earlier quoted context omitted.
Also, making decisions based on wishy-washy difficult-to-quantify human traits like "genius" and "sense of taste" seems unnecessarily risky, compared to making them based on measurements from repeatable tests.
https://en.wikipedia.org/wiki/Design_by_committee
You point out the need to pick the right measurement, and I agree, but it could be as simple as "What's the effect on conversion?" It has to be something! You can't just say "We're re-designing because I'm a HMI genius."