I have a question regarding King Lear, as well.
To start with, I've recently read Jan Kott's famous essay on KL, the one in which he drew a comparison between Beckett and Shakespeare's theatre and I was just wondering if King Lear's central theme could really be summarized as the fall of the world. Of course one could expand on this theme and noticing, for example, how much the use of metaphor is functional to the development of the subject.
But wouldn't it be reductive? If the world's falling down and so its morality - and, of course, the use of symbol itself - how much "weight" would one give to the individual stories of Lear and that of Gloucester, mirroring the King's?