Lear's basic flaw at the beginning of the play is that he values appearances above reality. He wants to be treated as a king and to enjoy the title, but he doesn’t want to fulfill a king’s obligations of governing for the good of his subjects.  An important question to ask is whether Lear develops as a character—whether he learns from his mistakes and becomes a better and more insightful human being. In some ways the answer is no: he doesn’t completely recover his sanity and emerge as a better king. His values do change over the course of the play.  He realizes his weakness and insignificance in comparison to the awesome forces of the natural world, he becomes a humble and caring individual. He comes to cherish Cordelia above everything else he places his own love for Cordelia above every other consideration, up to the point that he would rather live in prison with her than rule as a king again.  Therefore, the answer as to whether he is a good king or not is difficult to say precisely; however, he is most definitely a better person.