My list:
1. The police or some sort of law enforcement task force hunting Batman non-stop. Not only would Batman have to deal with a villain (or villains), but he'd also have to watch out for many, legal guns looking & trained on him.
2. Batman being more ruthless in inflicting pain on criminals (i.e. Maroni in TDK). I want everyone to just be afraid of him being near.
3. A new Tumbler. I love the Batpod and feel a car is more his thing.
4. Wayne Manor - with central A/C. :-P Yuck, yuck. Like with the Batpod, his mansion seems more him.
5. The Batcave with all the bells & whistles.
6. No love interest. Would be rehashing the 1st two films in a manner of speaking. Being Batman and having a love interest simply isn't in the cards.