Ok, I'm totally agreeing with Bob for his two major points: that Ben Afleck isn't as bad a choice as the butt-hurt fanboys think he is (the only reason they're thinking about his dumb and goofy shtick from a decade ago is probably because his last name sounds like the equally dumb and goofy "Aflac" commercials more than anything else), and that the problem with the DC movies of late is the lackluster writing.
However, I still don't think Afleck is gonna be a good choice because his work isn't dark, broody and angsty. If anything, this is gonna completely fuck up the movie in one of two ways.
1) The writers and directors shove the "Psycho Thug Batman" down Afleck's throat, and he flubs spectacularly because he has zero experience with dark and edgy roles.
2) They do a full 360, and play up Afleck's goofiness to the levels of the Adam West "Batman TV show" or the George Clooney "Batman and Robin movie", which, while probably a breath of fresh air from the gritty remake syndrome Hollywood has, will have even MORE legions of butt-hurt fanboys who think the "Dark Knight" has to be... well, dark. (That, or the overall story will be as dark as the "Dark Knight"/"Man of Steel" movies, but Afleck pulls a Nicolas Cage by deliberately playing up the hamminess of his performance to off-set the grimdark idiocy of the premise)
Any way you slice it, I don't think this is gonna be good set-up for the Justice League movie (even by the standards of fanboys immediately thinking it won't be as good as The Avengers), 'cause the Superman vs. Batman for the whole damn flick plot won't give them good reason for either of them to team up with other costumed do-gooders, and if the dark and edgy stuff leaks out to the other members of the League (Christ, can you even TRY to imagine a Wonder Woman movie in the same vein as "The Dark Knight Rises" or "Man of Steel", burying the bright and colorful aspects of her under a tidal wave of cynicism?), it'll just cement DC's image as alienated corporate schemers, who assume that all the cool, angsty kids wear sunglasses and black trenchcoats, and sulk in their rooms with the blinds drawn and the lights turned off.
Oh, and to all the posters getting into a hissy-fit because Batman was called "Mitt Romney with a leather fetish", it wasn't really meant as an insinuation he's the 1% elite, ultra-conservative superhero fighting the 99% poor, cripled, minority supervillains (although both he and Tony Stark are kinda tied with embodying it the most out of currently mainstream superheroes): he's just pointing out how the "crazy-prepared" interpretation of Batman is bullshit because his expensive gadgets do all the work for him, and he's never EVER really taken by surprise, going from being a pretty smart guy to having a level of omniscience that's bullshit for any human being. If they want to show the "crazy-prepared" side, Batman should be completely stripped of his gear, and forced to escape in a way that requires actual, on-the-fly wits, or gets himself completely blindsided by one of the bad guys, and is shown desperately throwing everything he has in a way that shows he's hoping at least one of his gadgets at least slows down the other guy long enough to GTFO.
And, yeah, just don't have "Superman vs. Batman for the whole damn movie", or even "Superman vs. Batman for two thirds of the movie before they fight the actual bad guy in the third act, and still see each other as incompatible opposites during the epilogue" movie. Cause if you're gonna make two founding members of the Justice League at each others throats, with the implication all the other members will be just as hostile to each other throughout the entire Justice League movie, you might as well scrap any plans for it right now.