I have always thought that stories based around Arkham Asylum are always some of the best in the comics. They allow Batman to demonstrate the full range of his capabilities, whilst creating great elements of fear and keeping tension high. That's why a movie should definitely be made around that premise and WBs should make their next Batman film around that.
So here's the trailer that I've made. Please hit the thumbs up and let me know what you think.
https://www.youtube.com/watch?v=SHSggyFHu4k