First, before I dive off into my reasons, let me explain just what I mean by "semi-canon." The folks up at Warner Bros. have already said they're reinventing Batman for the 2015 sequel to Man of Steel. This is exactly what I'd like for them to do.
I understand when different people collectively say the following:
"No! The Batman in Nolan's films couldn't even take on a pack of dogs. How could he stand up against Superman? Not to mention Nolan's trilogy was grounded in realism, with no mention of powers whatsoever."
Having the trilogy semi-canon would take care of all that. What I mean is that the EVENTS of those films still take place. Bruce Wayne was trained by Ra's al Ghul, he came back to Gotham and fought him there, he stopped the Joker and Two-Face, met Catwoman, stopped Bane, and somehow saved Gotham from an atom bomb explosion.
In doing this, those things still have happened, but Batman can still be the badass detective that everybody wants him to be. Allow me to continue.
1). The Open-Ended Nature of TDKR

The night was July 20, 2012. After a quite a few months of not seeing my grandmother, who is like a mother to me, I decided to take her to see The Dark Knight Rises. Batman is her favorite superhero.
We shared some popcorn and enjoyed the movie, and as Robin John Blake inherited the Batcave, I heard my grandmother gasp in glee. Walking out of the theater, she asked me if the next one would have Robin taking over as Batman. "No, grandma." I told her. "They're rebooting it."
She gave me a complete WTF face, and asked me why. "The director says he wants his trilogy to stand alone" I replied, and shook my head sadly.
"Now, that's just ridiculous," she said as we got in the car.
This is pretty much the same reaction I've got every single time I tell someone that they're already rebooting Batman. Just because they're changing the actors doesn't mean they have to do a full-on reboot, especially when they could continue the story so easily.
2). Almost Every Villain Could Be Used Again
With the exception of Two-Face, every villain from the trilogy could easily be used again. Scarecrow and Joker are still alive, Bane was never shown to be dead, and in the comics Ra's al Ghul always finds a way to come back to life. Hell, even Victor Zsasz could be used again if you needed him.
Which leads me to my next point..
3). The Joker
Who could possibly live up to the legendary performance that Heath Ledger gave? He definitely made the film worth watching. Sort of a continuation of my second point, if TDK trilogy is kept semi-canon, it would give the Joker a reason to seek revenge on Batman for keeping him locked up so long. The next Joker that appears on film he should be somewhere between Heath Ledger's version and the one from the comics; it'd give a sense of familiarity while still being original.
4). Three Years?
Call me old-fashioned, but I still think five years was a bit too soon to reboot Raimi's Spider-Man films. I understand the creative force behind it, but as controversial as Spider-Man 3 was, the ending left me wanting more. Just as The Dark Knight Rises did. Three years, and they're ALREADY rebooting? A freshman in high school that saw TDKR in theaters won't even have graduated before seeing a new Batman. I don't know, guys that's a bit much. Little kids won't understand it. Regardless on what your opinion is on the Man of Steel sequel, there's just no need to reboot this soon.
5). Tired, Weary and Seasoned
Ben Affleck's Batman in the MOS sequel is described as "tired, and kind of weary and seasoned." That would definitely describe the Batman having gone through the events of Nolan's three films. I mean, saving Gotham City from an atom bomb would most certainly leave you tired and weary, and he's already seasoned.
Again, thanks for reading, and give me shit in the comment section below!