If it's crap ... We'll tell you
WARNING: THIS IS A SPOILER THREAD.DON'T READ IF YOU HAVE NOT PLAYED THE GAME.............................
Ok, it seems like there are a couple hints pointing to a sequel, they are....
1. Harley Quinn's pregnancy test
2. Azrael's promise of destruction
3. Hush not getting caught
4. Hint of scarecrow's return inside boat.
5. Caldendar man escape
What is your idea for an Arkham city sequel?
1) I think the pregnancy test was more of something for us to say "oh snap!" and if there is another game, will probably be mentioned but not a main storyline. Harley isn't a formidable stand alone villain, and if she is pregnant or with a small child she would be even less so. Or maybe not! Maybe so grief stricken she becomes unpredictable?
2) This is my bet on a major plot for the next game. Ditching the prison atmosphere and opening up all of Gotham City so the actual citizens are in danger, not just scum. I found myself saying "cool" when Tyger was launching missile strikes against the prisoners. Wasn't in a hurry to stop Strange. I like Batman, but he is way too strict about his no killing rule. And they sort of forgot all about the "He knows I'm Bruce Wayne" thing. If there was a threat like that to the general population I might care a bit more. There had been threats to Gotham in asylum and city, but it was just other people talking about it, so it didn't carry much weight for me. "Gotham will burn, and you... you will burn too." Awesome. Yes Please.
3) Again, will probably be followed up in another side mission. Same with 4 and 5.
Not my idea for the next game, but my wishlist, like I said above, is to get out of prison. Play as Batman in Gotham City. Stop by Commisioner Gordon's office, go to Wayne Manor, Cruise in the Batmobile, play a few missions as Robin, Nightwing, Catwoman is always welcome. I vote yes for 2 player co-op. Can you imagine co-op missions that require two players for a predator mission. It would require Portal 2-like communication to time takedowns. Save citizens from random street crimes, stop a bomb from going off in a hospital, etc, etc.
A few questions about City...
A) They couldn't develop more of the cure right? So all the infected citizens presumably died?
B) Is it just me or is Batman a total dick to everyone? Oracle, Robin, Talia, Gordon... he is an asshole to every one of them... why would these people not be like "Fuck you dude, I'm not helping you anymore." The only people it seems he is decent to is Catwoman and Alfred.