It's....it's like they WANT it to fail....
They're going in the right direction, by making Batman an older, more experienced hero (told you it was a good idea!), but they've cast the wrong guy.
Now there's nothing wrong with Ben Affleck. People badmouth his acting, but I've never had a problem with it. He can also do the super-hero thing. The problem with Daredevil was the script, not the casting. Affleck did a fine job as Matt Murdock, given the tripe he had to work with. He just isn't Batman/Bruce Wayne, though.
On the Keaton-Clooney Scale, he's a full-on George.
He'd make a much better Superman than he would a Batman. He's even played Superman before.....well, he played a guy that played Superman (Hollywoodland, 2006).
The actor I'd have loved to see take the role of the Bat is Jeffrey Dean Morgan. He plays a relentless, grizzled bad-ass PERFECTLY.
At this point, I don't see a JLA film posing much of a threat to future Avengers outings.