About your example, I think we can explain the fact that even if shooting is his lowest skill, it's still pretty good compared to so I think your player is too good to see the clout of skills.
We should consider a player specialized in offence or defence, however it may be difficult to evaluate skills' impact as we do not see our player everytime during a game so maybe you're right.


And about the highlighted skill, I think they gain faster :
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My player who have been four or five years with me
As you can see the highlighted skills is higher than the others :
For the defensive skills, it is because I mostly train him for offence
But the "agressivité" is very low and I assure you that I always begin a drill with warm-up which gives aggression
So it may gain faster