Public speaker can be a very influential and a powerful position to be in. A person who is able to influence others and can make them agree with his or her viewpoint can be regarded as a good public speaker.
The art of public speaking depends upon the beliefs and interests of the speaker. While making an argument or delivering a speech it is bit obvious that the personal bias of the speaker might influence his or her arguments. Also the background which the speaker possess can hold a great value to his or her opinions and viewpoints.
But a person who can go beyond his or her personal bias , beliefs, opinions or pre-conceived notions and establish the true and just facts and then deliver a speech can be considered as a good public speaker. Public speaker must hold certain skills like empathy, truthfulness, should be unbiased as it is a very sensitive position as a speaker holds the power to influence people.