I have trained a *lot* of new roles and Special Abilities, and while there was a small drop in their performance during training, after, they have done well. The much greater majority of them anyway. I have learned before training a new role to try the player in the proposed position and see how he does, if he does ok I go for the role, if not.. no And with SAs it helps if they are in line with the players best attributes. Some players require a difference balance of attributes after gaining a new role, like when I train a D to be a wingback, I give him more offense points, etc.