I don't mean a big difference between grey and white skills, I think each player might have a best skill balance based on position, tactics, and opponent. For example, my DR had a great goal scoring rate for his first 5 seasons or more (would have to check screenshots of his stats and skill). While he's an effective enough defender, I couldn't maintain his skill balance, specifically the grey skills, and he scores rarely now.

My attackers are doing very well at near retirement, lowest Q ever, very unbalanced skills grey: white, but still I focus on individual skill balance. My philosophy - mixing unbalanced, older, low %Q players with higher %, younger players yields a team that is most effective at a lower team Q than your opponents. (My current season is proving that out).

I look it from a resource management perspective, I can fast train a few u-21 players each season, and save resources that won't go very far with older players anyways. I pick someone up at 18-19 and have a few seasons to see if theyre consistently effective in matches, and at 21 I can make sure they get to whatever %q I choose.