very interesting read. I agree that white skill is not equally important, for ST I like to focus training shooting, finishing, heading first and dribble speed str second.
I do have some experience with player that his white skill not even, I train this DC/DR until his his tackling positioning bravery around 190% marking 150% but everything else fall behind around 100% and he just perform badly every game while the other defender perform better with their white skill only 100-120%, so I decide to train the rest of his white to 120-130% and after that he start perform better. Idk if this is just coincidence or not but from then on I always make sure the other attribute not fall behind too much.