There are plenty of early Batman stories they can work off of, so that won't be a problem at all, watch Batman: Year One on Netflix or something, there's plenty they can work from..... but it's going to suck anyway because it's an entirely different team who have made 0 good games.
Which is a relief for me, as Rocksteady are a good developer, and Arkham City was full of problems as I have ranted about before, despite being a good game, leading me to never want to play a 3rd game by them, because it would be a bloated hell of annoyance and silly missions and find 100 of something, even more so than Arkham City.
So, now that this new dev is on board, it's going to suck, and I may play it once, then never again \o/