The next logical step is Batman and Robin
Let the movie take place...5 years from now
He is established, he is unfukkwitable now. Develops a relationship with a reporter Vikki Vale who is following Bruce Waynes recent philantrophic pursuits and attempts to help continue the work he started with Belle Real after The Flood.
They're out one night...Alfred keeps asking him to develop some sort of social life because he can't be The Batman forever
Bruce witnesses, of course, dikk Graysons family murdered by Tony Zucco who works for the newly released Sal Maroni
Maroni of course wants revenge against the Batman but will settle for the piece of shyt DA, Harvey Dent, who insists on meddling in his business
We get Robin. We get Two Face. We get Bruce having to explain to dikk (when he gets Zucco) that revenge has its limits and if they're gonna be partners, there has to be an understanding of that.
Etc. etc.
Simple...make it happen!