Let's get straight down to business...
1. INCLUSION OF MORE DCU CHARACTERS
Characters like Harvey Bullock, Renee Montoya, Vicki Vale, and Crispus Allen. Nolan has done a good job of including characters like these straight from the comics before, staying surprisingly close to the source considering the originality of the stories.
CHARACTERS ALREADY USED: Commisioner Loeb, Detective Flash, Sal Maroni, Carmine Falcone, Victor Zsasz, Henri Ducard, and Joe Chill.
2. REFERENCE TO FUTURE ADVENTURES
Nolan has said in recent interviews that he is VERY pleased with the ending of Batman 3 and how the character's journey end. This is something I am worried about. I want the ending to set up his future adventures as Batman with greater escalation of super villains. I hope that Bruce doesn't stop being Batman at the end of the 3rd movie because it will destroy any hope of a Justice League/Superman crossover.
I want the ending to be Gordon and Batman on the roof of Gotham PD with a new Bat-Signal similar to "Batman Begins" scene. Then on Gordon's radio a break out has occurred at Arkham Asylums's Level 5 wing: Joker, Scarecrow, and Killer Croc have all been released. This could include additional villains.
3. LINK TO THE REST OF THE DC UNIVERSE
If those of you can remember, CBM Editor Brent posted an article containing a plot outline of themes including a reference to Metropolis or Lex Luthor by Commisioner Gordon. This I HOPE is true. This would set fans a flurry in theatres and would indicate that a CROSSOVER IS POSSIBLE.
4. BATMOBILE
Batman can't exist without a Batmobile. I would be happy for the Tumbler to return as I really liked that design. A sports car like a Ferrari can't have all that tech fitted to it, whereas the Tumbler can. There are two after all, and Bruce Wayne has already used one. The Bat-Pod isn't enough.
5. NEW FEMALE INTEREST
I believe that the Nolans and Goyer have included a new love interest for Batman. It would make the story better as there has been a love interest in the previous two films. If there isn't, however, no biggy.yY ou can play Batman as being even more ruthless than ever due to the anger of Rachel's death. Vicki Vale or Selina Kyle could be easily placed into the film as a new love interest; and either would be interesting to see in comparison to Burton's films.
6. THE RIDDLER
I am one of the few that want to see the Riddler as a primary villain along with a secondary villain. If done correctly, it could potentially outdo Heath Ledger's incredible Joker performance. Robin Williams could pull this off. I feel in a performance similar to that he played in One Hour Photo and would really test Batman mentally and bring Batman's incredible detective skills to the table.
7. BANE & DEADSHOT
If you were having the Riddler, then you need a physical challenge to Batman. Who better than Bane? Question is, would Nolan go for it? I doubt he would go for it, but it would be interesting to see his take on the Venom powered powerhouse.
Deadshot can be used as a villain at the start of the film in the first act and first action sequence. He can be targeting Comm. Gordon after being hired by the mob and is captured by Batman.
8. HARLEY QUINN AND JOKER REFERENCE
This is what every fan wants to see: Harley Quinn taking a captured Riddler under her care to Arkham. Of course, she would then mention her working with the Joker.