Sorry for the rambling but here is what I think, hope its readable.
I can see what they are thinking though using Batman as the founder.
His mission is to protect lives and stop criminals.
By putting a team of superheroes together he has more of a shot at actually accomplishing that goal. (and by grouping seasoned veterans together he isn't putting children in harms way, these guys can handle themselves and do it anyway.). Its also realistic to think that the team would be funded by somone rich enough to do so, like Tony Stark in the Ultimate Avengers.
It also goes with this idea that he would also create Brother Eye (the satalite that watches everyone.) Then he also creates the OMAC robots to I guess protect the rest of the world or something, so that crime would eventually be wiped out.
So they seem to be creating a sort of Batman character where he is willing to do WHATEVER it takes to wipe out crime, no matter the cost I guess.
But here is why I don't like any of this,
In terms of story it turns Batman into one of those alternate future stories where the hero is pushed too far and he becomes a dark and twisted dictator who is willing to enforce his Big Brother type rules on everyone.
That isn't Batman, not now anyway.
In terms of his character I don't see Batman being able to do all that. Maybe he could fund and lead the JLA (I'll get back to that later) and maybe even create Brother Eye, but I really can't see him making the OMACs.
For one thing he isn't a character who has the ability to create majorly advanced (AMAZO) like robots. That sounds more like a Dr. Doom or Iron Man character than a Batman character. Plus why would he need the robots if he has a team of the worlds greatest superheroes put together?
(unless it is like the Green Lantern things, where the Guardians created the Sentinals but they were to harsh, so they created the GL Corps.)
Batman funding the JLA and leading them:
I don't mind him funding them, in a way that it wouldn't lead back to him,
But I do think it is out of his character to lead them. He is a dark brooding character. Someone who has been on his own (besides Alfred) most of his life and sort of doesn't let anyone in. So I am not sure it is in his character to want to lead them, then again maybe he sees this as the only option. Maybe he sees leading the team as the only way to stop crime, and he puts his own feelings behind that goal.
So I am willing to give the film a shot, but I am also sceptical.
I mean the idea of a Batman who is setting his ultimate goal to stop crime into motion sounds cool. A Batman who starts the JLA and uses Brother Eye all to stop crime might be very interesting.