My idea would revolve around Blake as Batman, in a Gotham that is recovering and rebuilding. Meanwhile things taking a more fantastical turn in terms of villains - the fallout from the nuclear blast starts resulting in some side effects and mutations, one of which is a sewer thug mutating and getting deformed badly (Killer Croc) and starting to cannibalise people, taking them into the sewers.
Meanwhile out of the ashes of the city, while there is real hope on the streets and spirits are high after being saved by Batman, the new generation of mob bosses also takes hold, with two opposing factions. Roman Sionis on one side, Oswald Cobblepot on the other.
Then of course, you have the Joker who's whereabouts are unknown as during the siege of Gotham he disappeared from Arkham...
Between all those things, I think some pretty awesome stories could be told.
All of that could potentially end with Robin Blake being badly injured, and Bruce potentially having to return once more... The Dark Knight Returns.
