• It's just a script. WB has commissioned many, many JL movie scripts, and you can see how many JL movies that's resulted in.
• Beall is also writing the Lethal Weapon remake and the Logun's Run remake, and Variety implies he's turning those in first.
• We have no idea how good Gangster Squad will be, and literally the only thing IDMB has him listed as writing are scripts for Castle. Castle's a fine, Fillion-full show, but I don't think it suggest the talents to write a good Justice League movie.
• It's Warner Bros., and they always fuck this up. Even when they actually make the movie, they usually fuck it up.
But there are a few reasons why you could get excited.
• Avengers has made well over a billion dollars. Warner Bros. has seen that superhero team movies can do quite well, so if there's a time to actually make the damn thing, now is the time to do it.
• I thought I had more, but I guess that's it.
So. There you have it. Right now, I'm just going to pretend this doesn't exist, because it probably won't.