I think they are great women for being good wives and mothers to help hold a family together when times are good. I’m just not sure how well they would do when times are not good. Neither Kate nor Camilla strike me as Boudicca material.
The real test is: If Camilla had been in Diana’s shoes, how would she have faired? How would Camilla have coped with being chosen as a wife because of her virginity? Married to a man who loved another woman but needed her to produce heirs because she was a virgin?
And if being a good wife and mother is all that you need to be to have a claim to the crown practically every woman has a right to the crown.
Most people can be uncomplicated if they have the right circumstances (as you say, reared in privilege, loving family and good schools to cement all of that).
My point is that it shouldn’t be so easy to have a claim to the Crown because the Crown is THE symbol of justice. And there is nothing more complicated than justice and injustice.