Finally, I read every post just to be up to date on what has been mentioned.
The biggest thing I picked on was some people's request to have more detective work with the mafia and more building a case and collecting evidence against criminals and working with the police to put them in jail. Now that sounds cool and all but if the third game follows the last two the game will take place in a city that is in total chaos, which doesn't fit in with the detective work. Just my two cents.
Something that bothered me while playing new game plus on hard was that while the combat did get tougher the rest of the game didn't. Same thing applies with the rest of the difficulties, the only thing that changes is combat. I think that something that should be worked on is to try to make the crime scenes and stuff that doesn't involve combat more difficult as the difficulty chosen increases. What I mean is that they shouldn't guide us and take our hand and say this is what you have to do, scan it, done. It would be interesting is scanning was scrapped altogether for harder difficulties and you have to pick up the evidence with just your skills. Much like the counter sign disappears in new game plus.
Other things that I would like to see are more balanced side missions. While the Riddler's side mission was pretty massive there were others who seemed pretty short, like hot and cold and the mad hatter one. I also had trouble with the Acts of Violence side mission in my latest gameplay, after I finished the whole game I had to roam for 30 minutes every night for several nights until I found some abusive thugs. As well I had trouble with the deadshot mission, I basically only had the first victim by the time I finished the main story so it seems somewhat strange when you finish the side mission which ties to Strange when he's already dead. You'd figure Deadshot would not kill his targets if the man who is paying him died. So what I'm asking is more balanced side missions, I understand some have to be longer than others, and better pacing for side missions who are affected by the outcome of the main story.
I enjoy the idea of a No Man's Land kind of deal and I think it would work well because Rocksteady could potentionally cut off some zones from others, for example Robin could be stuck in the Pallisades and Batman can take the rest of Gotham with Catwoman while Batgirl and Nightwing are in Arkham and Bludhaven respctively. That way they can adapt those regions to fit the character's needs movement wise. What I mean is that a character like Nightwing would have trouble moving from one point of Gotham to the other without gliding but a smaller section like Bludhaven with taylor made buildings.
Villain wise, leave the Joker dead please and just bring a good selection of villains and make the easter eggs from the previous games worth it. I understand that not all of them will end up in the game, like Harley's baby but I feel it would be a disappointment for the fans who sit through countless hours of easter egg hunting if at the end they didn't mean anything.
Finally, I feel like traveling in vehicles is not a great idea. I would rather have a deeper game with more things to do than driving around town with some races and car chases.