Yeah, Death in the Family is one of the most well known Batman stories like Red Hood, Killing Joke, Long Halloween, and Knightfall. While most people don't know the full details of the comics, they know the gist of the story developments: Jason dies, Jason comes back as a villain, Joker cripples Barbara, Harvey Dent becomes Two-Face, and Bane breaks Batman.
An Amadeus descendent would have been interesting. If they really wanted to go wild with it, they could have turned Amadeus into a Simon Hurt character where he's functionally immortal and he spent all that time in his own Asylum since being admitted but was forgotten about and lost among all the chaos that happened throughout Arkham's years. I recall in the comics he believed his family was haunted by an evil Bat spirit, so that would be solid motivation for going after Batman.
