Hey, I'm not really sure what your core area of study is - are you doing critical literary theory? Let me know and maybe I can help more but I guess what you are looking for is the things that seem to be valued in the context of the original Lear, I mean just on it's own without any modern doing-over like say
a wise king who knows the danger of a divided kingdom, an honest adviser ie Kent, loyal children, an ability to have insight into the true nature of others, obedient women etc) and then look at how certain values have changed so that in a contemporary production we have lost the meaning behind the kinship stuff and certainly see women differently but some of the stuff the play 'values' still has resonance for us today like maybe: a certain view of the bleak, cruel, indiscriminate hand of fate; family loyalty; sound insight and judgement.
A modern interpretation might seek to convey some (no one can do 'all' of Lear so its about choosing) of these shared values, or things that have meaning, but deal with other aspects of the play, containing values which conflict with contemporary tastes, in a completely different way. So Cordelia is strong and forthright, or Goneril and Regan are victims of Lears sexual abuse - google 'A THousaand Acres' for an example of a feminist reading of Lear which tries to handle some of the values about obedient women which might not suit a modern audience.