I... WHY?! Why would you do this? AGAIN?! Exclusive playing as the Joker on PS3 was bad enough (although it was just some extra challenge maps). But making some Scarecrow missions exclusive? Arguably the best type of missions in the game? Grr...
Then again, they'll probably just turn out to be either playing as Scarecrow (which is cool, but not that cool) or Scarecrow themed challenge maps. (Which might be cool, or might not be. Imagine a predator map while affected by the fear toxin yourself! On the other hand, the Scarecrow combat challenge in Arkham Asylum is something that I wouldn't mind missing.)
If the PS4 turns out to have exclusive story-based Scarecrow missions though, I will not be happy. My intention is to get this on PC.
HOWEVER: I have to say, city navigation looks very cool, both in the batmobile and when gliding. As did that multi-person takedown.