1. Some sort of cogent explanation for why every single Doctor, Saint, catechism and other authority post Trent were in the wrong and now have need of the saintly Feeneyites several centuries later to correct them.
2. For why St. Bernard, St. Bonaventure, St. Thomas and all the medieval Doctors and scholastic theologians especially after Pope Innocent II and III were also wrong, while the heretical Peter Abelard was right.
Both of these are very simply explained. It's for the very same reasons that centuries of Doctors, saints, and theologians were wrong in following St. Augustine about the fate of infants who die without Baptism. In that case, also, for about 800 years EVERYONE got it wrong, until the "heretical" Abelard came along and overturned this teaching. In the end, the Church sided with Abelard on this particular issue.
St. Augustine had a LOT of authority in the Middle Ages. In fact, it had been exaggerated to the point that the Church felt the need to condemn the proposition that the opinions of St. Augustine can be held even above and against the teaching of the Church. But there wasn't a lot written about BoD between the time of St. Augustine and then the early scholastics or pre-scholastics ... except a rejection thereof from St. Fulgentius, a disciple of St. Augustine.
What happened then was that Hugh of St. Victor and Abelard were feuding over BoD. Peter Lombard couldn't decided between these two opinions, so he wrote to St. Bernard. St. Bernard tentatively sided with the Augustinian opinion (as he saw it, since nobody was aware that St. Augustine had retracted it), saying that he'd rather be "wrong with Augustine" than right on his own. Peter Lombard then went with that. St. Thomas and other early scholastic theologians picked it up from there. And once St. Thomas had that opinion, it went viral, so to speak. But at no point has the theological note risen above that of an opinion of speculative theology. So it wasn't actually post-Trent but, rather, post-Aquinas.