There's a pdf making the rounds that claims to be the script for Batman v Superman: Dawn of Justice*, one that I've had sent to me a couple of times. I discounted the script - it's full of spelling and punctuation errors and it feels just a tad too fan-friendly to be real.
As reported by Latino Review the script indicates that not only is the film packed with heroes - Aquaman shows up in the opening scene - it's packed with villains. As Latino Review says it features Zzasz, Morgan Edge (another corporate bad guy in the Superman comics) and assassin David Cain. And that's just the tip of the iceberg - if this script is legit it contains other big time baddies who haven't even been hinted at, but I don't want to pull a HitFix and spoil the end of a movie more than a year out.
LIke I said, I'm on the fence about the legitimacy of this script. I trust El Mayimbe's network and the other information he has beyond this script, but something about the actual script itself - whether it be the errors or the cascading fan-service (Kord Industries, Jason Todd, a Shuster Street in Metropolis, Kyle Rayner, Carrie Kelley, Thanagar, mentioning Hob's Bay, the President is named Diane Nelson, who just happens to be the president of DC Entertainment) or the fact that tonally it is nothing like Man of Steel (Themyscira has an embassy in Metropolis!) forces me to remain humbly skeptical. If this is the script then Warner Bros has learned some lessons from their last couple of movies, although I worry the sheer weight of fan service in this script could crush the film.
I suppose we'll see if any of the coming casting announcements fit any of these roles that have not yet been announced.
* the actual title of the movie.