Before Batman Arkham Knight, John Noble began voice acting as Unicron in Transformers Prime and then as Braniac in Superman Unbound. Now because of how Scarecrow's voice sounded in the past few gameplay trailers to Batman: Arkham Knight, John Noble is now heavily speculated to be the voice of Scarecrow as one of the main villains of the game. It makes sense too after all the character's voice had many of us confused with those like Richard McGonagle, Daran Norris, Lewis Black, Kevin Conroy, Troy Baker, Kirk Thornton, and James Horan.
Plus we shouldn't forget that Castle star Stana Katic voiced Talia al Ghul in Batman Arkham City and she did co-star with John Noble in Superman Unbound.
Still Noble's voice as the Scarecrow in Arkham Knight sounds a lot better and much more fitting for the character than Dino Andrade's voice in Arkham Asylum it make's the villain sound much more fearful when inflicting people with fear gas.
Some people think that the Joker is impersonating Scarecrow or Arkham Knight because of the twist in Batman Arkham Origins that made him steal the main villain spotlight from Black Mask just by making him revealed to have impersonated him as well as having to take so much of the spotlight in Arkham City by having Batman poisoned throughout most of the main story of the game as well as dying after Hugo Strange as well as being unpredictably smart and coming back alive from situations where he was thought to have been dead. Even with him being Batman's arch nemisis overall. But now it seems to be unlikely.
If true, John Noble's voice will be real sinister and epic for the upcoming Arkham Knight game. For now we wait.