Despite the way Cosby ended up, his show and his comedy were outstanding. Not only were they entertaining, but the lessons and subject matter were for all audiences.
Also, I believe it was the first show that showed a Black husband and wife as professional well educated people. He was a doctor and his wife a lawyer. Other shows, (Sanford and Son and Good Times,) continued to show Black people in an unflattering, poor, ghetto, lifestyle.