I think it would be a great idea to have individual defensive matchups for each game. I have recruited players in the past who are great defenders capable of guarding multiple positions. By having the ability to put a great defender on an opposing teams best player I believe it would add incentive for teams to recruit defensive role players. 

On the flip side it would also give players a chance who have an average or below average defender on an opposing teams player who isn't an offensive threat.