
I think you guys are forgetting about the death of the main protagonist in the movie vs. the book. The main reason they WOULD NOT be able to make a second movie without redoing the first is because they KILL OFF the razaac!!! which means there is no bad guy in the second or third to deal with. And since durza was killed, they would have to introduce an entirely new shade in order to create more razaac, and then have them actually look and talk like they are supposed to!!