Lear and Gloucester are victims of folly and blindness. In Lear, folly results from blindness--blindness which is not physical but intellectual, due to lack of judgement. In Gloucester, folly, resulting from moral incapacity, results in physical blindness.
The battle between good and evil lies as the basic thematic discourse in all English Renaissance tragedies. In King Lear too we have Cordelia, Edgar, Kent and, may be, Lear's Fool representing goodness, while Goneril, Regan, Edmund, Cornwall and Oswald represent the forces evil. Lear and Gloucester are no simplistic representations of either good or evil. Both of them illustrate folly and blindness; both of them suffer for their lack of wisdom and judgement; both of them are pitted against their evil-minded offsprings--Goneril, Regan and Edmund--who embody obstinacy and pride as manifestations of evil.
I'm not sure blindness & folly are so much pitted against obstinancy & pride as they are examples of it.
This seems like a complicated question. We might clearly delineate examples of good (Lear, Kent, Cordelia & Edgar) and evil (Edmund, Goneril, Regan,).
Lear's blindness is metaphorical - he can't see what he's doing in dividing his kingdom and abdicating his rightful throne. He is a king, and yes, that patriarch people often think is so bad. Perhaps it is fundamentally wrong to have a hierarchical system; however, Bloom's comment on the reactionary position seems best in his book "How To Read and Why": we don't understand the origins of what we call patriarchy.
You might then argue that all become's folly when the rightful king abdicates - and can't see truly who is good and who evil.
It seems that this blindness is perhaps perpetuated by his obstinance, pride and error. It is like Brutus, who thinks himself so honest, that he is not susceptible to dishonesty.
I just have to say, I really find the posing of the question very complicated and I'm not certain it is tenable.
Perhaps another way of looking at it is as Goneril and Regan (and Edmund?) as obstinate and proud, with Lear as blind and follying?
Maybe that's the way to go - then perhaps I can see something working.
That's perhaps even interesting; however, it is strange: we have two competing dangers fighting - it seems we want no one to win in that battle. Maybe in that sense, it could be metaphorical of society - always dangerous. Again, though, I become stumpped again. Have you got an idea of where you are going with it?