What would be a universal thesis about "status" that would allow for an insightful examination of King Lear?
The term "status" is very broad, but when considered within the context of the play, the ideas of social status and political status come to mind. Numerous characters, especially Lear and Cordelia, experience profound changes in social and political status during the drama; how these changes affect them and determine their courses of action develop the main plot and contribute greatly to the themes of the play. Other characters, as well, are developed in relation to their status in society and their political power, or lack of it. One universal thesis you might consider, based on the characters' actions, would be this:
Social and political status do not determine moral integrity or the value of a human being.
This thesis could be supported by examining the characters in King Lear in terms of their thoughts and behaviors. Holding high social status and wielding political power do not guarantee moral behavior, but they do not always exclude it, either; genuine humanity exists apart from one's status.