Sadly the ambiguousness of CoH makes role 'learning' hard. Its a great system, because anyone can do anything, some just do it faster. But it makes 'training up' hard, because the same task a tanker can do, a defender might not be able to handle, or even differently, the task an Invuln Tanker can't handle, a Dark Tanker would just walk through. There's so many variables in this game its what makes it so unique.