What does the play tell us about the qualities of a good king, a ruler of any kind in both personal and political settings?
I think that the drama speaks to a couple of elements that can be immediately seen in the personal and political realm. The fundamental issue at hand is that Lear views love as synonymous with praise. It is Lear's own ego and his own sense of self that ends up blinding him to the deviousness around him as well as the love that is around him. This ego and sense of individual pride or hubris causes him to shun the daughter who loves him, embrace the ones that don't, and eventually initiate the process of him losing everything of material value. In this, I think that a major demonstration of how a good ruler or king is one who does not make decisions based on their own sense of ego is evident. Lear proves that an effective ruler will make decisions not in accordance to their own ego, but rather in a manner that shows a sense of prudence and deliberation. Lear's emotional rebuke of Cordelia and his odd embrace of Regan and Goneril represents a failure on both father and regal levels. It is Shakespeare's genius to make Lear a failure on both realms. In both levels, Lear's ego and sense of self, as opposed to operating in the domain of something more transcendent and worthwhile, is what seals his own fate. His suffering is a result of his own ego. In this, Shakespeare makes the case that an over-reliance of the selfish ego to make decisions results in both unspeakable personal pain and political tragedy or political loss. The qualities of judgment, forebearance, and caution are traits that Lear does not show nor reflect in the opening to the drama.