Why is there so little preaching and teaching on the Crucifixion today?
It’s complex, but I identify two reasons. The first is an almost wholesale retreat from the penal substitution theory, which was an unfortunate development in late 18th- and early 19th-century Protestantism. It held the field for a while, especially in evangelical circles. It was overwrought and overly rationalized and taught in a way that sabotaged the unity of the Trinity [as if the Son were placating the wrath of the Father]. It is not in the spirit of the Passion narratives.
Second, people don’t want to hear about sin, suffering, evil, or judgment. The African American church has something to teach us here. They’re not afraid to talk about judgment. People who have suffered under tyrannical, cruel, brutal regimes understand the need for judgment.