You have the right idea, but your horse ran over your cart. The four rules are a foundation for that safety mindset. You start with very concrete, straightforward (not literally perfect, but frankly not that hard to understand if you get out of your own way) absolutes. You progress from there to understanding why the rules are in place, how they interleave, and why there aren't exceptions. You then build habits that become part of a deep safety mindset. Clint Smith describes this very well around the 3:00 mark of the video linked in this thread.
In other words, the four rules are the best way to get to the safety mindset you rightly describe as the ultimate goal. They are "how that could be effectively taught."
It's not about anything of Cooper's being sacrosanct; it's just that well used and widely taught formulations are well used and widely taught for a reason.
I tend to think that people who want to 'improve' the four rules (and the color code, and so forth) are not necessarily choosing the best path to enhancing the state of the art. I'm disappointed to hear that major trainers go down that road, but I only have so much of a training time budget anyway.