The dichotomy of Grant's heart giving out being the catalyst to the rise of Deathstroke's terror on the Titans and Joey and Rose's inevitable introduction into the team vs Dick being shot near the heart being the catalyst to the rise of Nightwing during the Judas Contract storyline (which only ever happens because of Grant's death)
The parallel between Joey getting his throat slit by the Jackal because Slade refused to back down from his code of ethics vs Jason getting his throat slit by Bruce in front of the Joker because Batman refused to back down from his code of ethics
Rose and Cassandra both never getting the proper chance at a true father-daughter relationship with either Slade or Bruce because the death of the brothers who had come before them have already weighed heavy on their father's souls.
Sons with heavy hearts, Sons with slit throats, Daughters with eyes who can see it all and the fathers who continually fail them despite how badly they desire for happy children.