Referring to your maniac, sometimes that does happen, I mean, I once had a backup SF and he put up a 52 point game. He was nothing special. And to your other question about hidden skills,
Its been thought players have an aggressiveness to them, some players commit very little fouls, and some commit a lot of fouls. This is known just to be their nature, but sometimes is also dependent on their defense.
So if a player fouls a lot, its just like a tendency and there's really nothing you can do about it unless you're willing to take his talents to South Beach.