He’ll Be Older & More Experienced

By the time Batman v Superman: Dawn of Justice hits movie theatres in 2016, Ben Affleck will be into his 44th year. Compare that to Michael Keaton (into his 38th year in 1989 when Batman was released), Val Kilmer (into his 36th year in 1995 when Batman Forever was released), George Clooney (into his 36th year in 1997 when Batman and Robin was released) and Christian Bale (into his 31st year in 2005 when Batman Begins was released) and you realise that this Batman will undoubtedly be an older version.
Not only will he be older, he’ll also be more experienced. Affleck’s Batman will be a veteran crime-fighter who had actually retired several years prior to the events of the movie but returns to combat the Man of Steel.
As a result of that, there’ll be no origin story this time around either – a fact that will definitely differentiate him from previous versions in itself.