So just to show what I'm talking about I'll let you compare these 6 players. First 3 are from my team, second three are from the team I was talking about. I left out the overall rating on purpose... Would you think that there is a 11 point gap after 12 league games between these 2 teams as well as +33 goal difference from the second team?
I mean, don't get me wrong, I know he invested a lot into his team and I'm sure that he deserves to win the title as these are good players and the white skills are also quite high, even though they are not trained in a very good way, in my opinion.
I just want to point out, that in the current state of the game, it might not be worth to start training with a lower overall player and invest your greens to get a high gap between white and grey skills, if you want to maximize your potential in the league, cup and CL and don't manipulate draws.