I like the idea at the beginning if bane is used, that bane begins using syringes, then has the implants, and begins using more and more, until the final battle in which he has Iv's hooked up, showing the trend of addiction.
In the story I created a while ago bane has a cult like following, that would be ideal, to show a lot of impressionable youth and thugs, and even some rich people, scared by recent events, what if bane offers protection, true protection from the insane, although his true motives are to destroy gotham, and create the ultimate utopia, which he claims would be no mans land, it would be owned by everyone, he tries to drive gotham into anarchy, first by distributing venom, then by giving his gangs tasks(like tyler durden did in fight club), he slowly begins killing batman(beating him up), he lets out all the inmates at arkham(this could be a moment showing the joker, scarecrow, killer croc, and some other rogues), and in the final battle Bane should use a machine developed by janus industries(black mask corp), it emits shock waves for controlled blasting without using explosives(it was deemed to dangerous, along with venom), he modified the machine(which is partially based on a tesla contraption), it break down the city under gotham(large sewers, tunnels, caves, and even a section from the 1920's that was literaly built over), the earthquake like effect will be magnified by several bombs placed under the city. Batman must stop all of this in the final battle, in the end all of the inmates of arkham are out again, and he feels as if batman must live on, he must never die, so he must never stop being batman in exchange for a normal life(this could set up a sequel with another director and robin).