Okay, so when it is first revealed to you, it isn't as big of a surprise as you first think. Especially as the Joker's taunts towards Batman concerning the disappearance of a certain Robin.
Could there have been a better identity than Jason Todd? The fact that Todd has only ever been mentioned as The Red Hood in the series so far, it is kind of a strange choice to go down the path of the Robin that Batman lost.
It seems more of an interesting choice as the story has a personal twinge to it for Bats adventure through the game. Also, him not being the mastermind in the first place is kind of strange to make him the title character.
So, is there anyone that could take the mantle? Well, even if it somehow turned out to be Ras-Al Ghul. That'd still be a better fit for the series, since Todd has never even been mentioned in the games as a former Robin, apart from his Arkham City character profile as The Red Hood.
I have no real reason being too upset about the Knight's identity, but within the context of the previous titles, it does confuse things in regards to Robin. Especially as there are only six months between the Robin-less Asylum and City's Tim Drake. This gets even more confusing when you take in to account Batgirl's 'A Matter of Family' DLC.
Tim Drake is Robin in the DLC, having never once been mentioned in Asylum, it seems kind of odd to find him in the prequel as Tim Drake. Therefore, it should really be Todd or Grayson, but as we've also pointed out to people before, this could be still be set after the disappearance of the second Robin to don the mask.
How does Robin's timeline add up? Let's hope for some Jason Todd DLC to fill in the Arkham Knight's backstory a little more.