Take this with a grain of salt, but the Batman Arkham Videos channel just released this video detailing an Easter Egg in this game possibly hinting that Batman will actually return in a future game.
You know, assuming that Rocksteady actually continues existing for that long, and the guy was actually correct when it came to decoding the Easter Egg.
Tl;dr: There's a bunch of calendars spread out throughout the game that have a bunch of random dates circled with the final one's date being marked with a bat. When you order all the dates by month, and then convert the days marked by what letter they would correspond to (ie; Feb 5th=E, and shit), you get the message "HE WILL RETURN".