Actually, this idea was the first thought I had when roles were implemented, it would be damn good to have something that described the usual playing style, even if it was just dependent on the skills, i.e. players with high JS and JR get the shooter role, or something like that. That could be the kickoff for something more elaborated as this suggestion.
Roles that affect training are specially attractive to me, having players that tend to be more of a passer, a defender or a shooter could make the game much more interesting.
It could also be gradual, like, clutch players could be 5-star game winners or just slightly better at the last possessions and that would also reflect on the negative end of the role.