Batman (action RPG)
Take the free roaming open world of Grand Theft Auto, and create an vast, epic Gotham City. The main storyline would feature Batman rounding up all his enemies who escape Arkham early in the game, while at the same time dealing with the arrival of an all new league of shadows led by Ra's Al Ghul.
Batman would earn points for taking missions from Commissioner Gordon, completing "Bat signal" missions, and solving The Riddlers riddles that are spread out throughout the city.
Also, completing random heroic tasks through out the city. These points would be used to purchase new gadgets and tech upgrades for vehicles and gear.
The game features 16 main villains, Ra's Al Gul (and his league of shadows), The Joker & Harley, The Riddler, Two-Face, The Black Mask, The Penguin, Catwoman, Scarecrow, Poison Ivy, Killer crock, Carmine Falcone, The Ventriloquist, Mr Freeze, Man-Bat, Clayface and Bane.
Each villain gets a 6 chapter arc (like the comics) and each chapter would be referred to as an "issue", each issue with it's own cover.
gameplay relies heavily on 3rd person gaming, rotating between different modes.
On foot, Batman can remain grounded with the citizens of Gotham or he can take it to the roof tops (which is more fun once you have acquired a grappling hook and the glider add-on to your cape).
Don't like to go by foot? Like GTA, gameplay changes when in Batman's vehicles, with over 9 different Bat mobiles(including movie and comic versions), a bat cycle and bat pod (from the dark knight), a Bat-boat and the bat plane.
The combat system would be similar to "Jade Empire", using all the techniques in Batman's repertoire.
For voices, I would go with Kevin Conroy, Mark Hamill, and pretty much everyone else in the animated series though the LOOK would be inspired by Jim Lee's "Hush"