Okay, to build off the Under The Red Hood idea and my own desire to see a larger Batfamily, how's this for a modification to the story:
Tie in an adaptation of Son of the Bat, increase Nightwing's role, and go ahead and make this a kind of war of the legacies.
In one corner, Batfleck as he tries to reconnect with Nightwing, who broke with him over Bruce's darkness after the death of Jason Todd and the injuring of Babs; Dick is here the son who is actually better adjusted than the father, and maybe even practices an even less Kill-count heavy combat philosophy than Bruce's "I'll allow manslaughter in the heat of battle" one. Have Jenna Malone play Babs Gordon as she starts to take over for Alfred and prove herself both back on the road to recovery and better at some tech jobs than Batman himself.
In the next corner, Joker returns to Gotham because a new Red Hood has appeared. I'd make his part in the storyline larger, too. Go ahead and make him and Jason start a war over Gotham, thus giving a reason why Dick is in town. His legacy is Jason Todd as well, and he enjoys that point once he realizes who Red Hood is. His goal, aside from just proving himself deadlier than his "off spring" Red Hood, is to finalize the corruption of...
...Damian Wayne, who is arriving in Gotham alongside the Red Hood as part of the vanguard of Ra's Al Ghul's forces. Except it's not Ra's- Talia has successfully and quietly usurped her father's throne, and she seeks to make one last appeal to Bruce to start fighting like Red Hood does, using the ethos argument of how dangerous Joker is, and the pathos of returning two sons to him.
So Jason is effectively in the middle of all three sides, acting as a combination crime boss and vigilante. And Bruce has to deal with two of his major enemies while they, and his former apprentice and newly discovered biological son, duke it out in his city.
Now, me, as a 1990s fan, I'd go ahead and throw in Tim Drake as one of Jason's old internet sources and Dick's apprentice Red Robin, and probably Cassandra Cain as a member of the LoA Batman recruits with the help of Damian, who she's the bodyguard and older sister figure to, and Catwoman as one of the few rogues Red Hood won't target for death but instead try and recruit, leading to Queenpin Catwoman for a future Birds of Prey movie, in the same way Dick, Tim, Damian, and Jason could fit into numerous spin offs as well.
But that would probably be too much.