3. Puts The Man In Batman
The most popular modern depiction of the Caped Crusader in the past few years hasn't even been on film or TV, it has existed in a video game. Arkham Asylum is the wildly popular single-player game series that lets players fight as Batman against his collection of deadly rogues. This interpretation is extremely successful, and this version of Batman has already been rumored to be the template of the next film adaptation for the Dark Knight prior to the Batman/Superman sequel announcement, so it is by no means a stretch to envision a brooding five-o-clock-shadowed Affleck donning the cape and cowl and blending right into this Arkham-styled Batman.
The Dark Knight Detective in Arkham Asylum is tall, dark, with chiseled features masked in dark stubble. All features Affleck already possesses in spades.