In the recent article about extending ASP.NET 5 identity model, the author add some custom properties to the basic IdentityUser class, and some basic role-based identity management. However, the author did not discuss modifying, extending, or working directly with Roles beyond seeding the database with basic roles with which to manage application access.
There are two reasons to extend the basic ASP.NET IdentityRole class and working directly with roles from an administrative perspective:
ASP.NET Identity User is fairly easy to extend.
When roles are used to enforce access restrictions, they are basically hard-coded; therefore, it gives the administrators the ability to add, modify, and delete roles.
Read the rest of the post here: http://www.codeproject.com/Articles/727054/ASP-NET-MVC-Identity-Extending-and-Modifying-R