Re: Someone please explain why....
I think the idea is that Gotham may not need Batman again but just incase, Bruce set up a successor who would be motivated to take over. Because the Dent Act means zilch now, and the city may or may not be vulnerable due to Batmans death. So organized crime may start to rise up slowly or if Joker returns in some shape or form, or if a serial killer decides to make his/her mark...Gotham would need Batman 100 %. But it may not even lead to any of this. And that's the point of the end. Or if it does need Bats, it could be just for a one-off appearance to scare the **** out of some new criminal (and thus scaring the city more than ever) since they would look at him as a dark spirit watching over them.
But i get what ur saying, because it could be a good setup, for "Gotham is strong enough to move forward on its own".