Acting is beyond being stereotyped. As an actor, you should be able to interpret any role given to you, as the script dictates.
Being stereotyped in movies limits actor while versatility helps him blossom.
Check out how these actors interpreting the roles of mad men.
A couple of Nollywood actors left the luxury roles they are known for and played the role of mad man in movies. Who interpreted the role best? Whose sight do you think looks convincing as a mad man?