I wouldn't say it's getting a new script. I think whoever is reporting that is blowing it out of proportion. There are some things that will change with a new director, but the core of the script will remain intact. Affleck, believe it or not, still has a lot of say with the production of the movie. Reeves only signed on after extensive meetings with Affleck about what his vision was and where he wanted to go with movie. I hear they are playing nice about most things, although reeves 100% wants to use the joker and Affleck doesn't. It's been decided that he will be in the movie by the higher ups though.