Unlike Smallville, this can definitely
The key is that if you're ignoring Batman, you have
to ignore Joker, Catwoman, and Two-Face. Don't get cocky and re-write comic book history like Smallville did.
The biggest villain names you could PROBABLY get away with are The Riddler and The Penguin.
Other than them, stick to:
Killer Croc (if realism is loosened up)
Clayface (if realism is loosened up)
Man-Bat (if realism is loosened up)
^ Villains you'll NEVER see in a motion picture. Give these guys the spotlight they deserve.
I'm VERY excited for this.