Actually KOPS is not as arbitrary as one might think - as many think...
KOPS does take into account one major factor which affects both muscle engagement and hip angle/power delivery.
KOPS adjusts for femur length, which in the pedal stroke is the factor which greatly affects and determines muscle engagement, hip angle and power delivery, when assuming a 'competitive' position for road cycling. The range of position needed is greater than what might be indicated - but then 'On the Rivet' was and is a very common condition for many races and sections. Same for 'out of the saddle' and having your butt nailed to the saddleback.
KOPS came about as an anecdotal method to what was yet to be shown by science, as a good balance position for varied riding conditions.
I don't really have any investment in KOPS, but it does work for a starting point for competitive road cyclists who must start with some indicated point.
Whatever 'balance method used might be good for, it's in no way addresses the above mentions factors.
It does help riders who are carrying a large mass in their torso - generally less concern for most competitive cyclists.
Personally, "Balance Method' is as good as putting the saddle mid-rail.
Ride On
Yuri