The main issue with Humane Vitae is that it set an absolute in place against birth control rather than understanding that each person's life and circumstances are unique.  So a woman who has had multiple complicated pregnancies is treated the same as a couple who wants to be childfree.  (Although I am really not sure why a couple who doesn't want children should be shamed.)  This is the same way that divorce and remarriage was treated.  Amoris Laetitia begins to correct that black and white reasoning.  Each person's life is unique and we cannot fit people into neat little boxes.