Villains
7. Jason Todd
Batman's former ally turned enemy offers one of the best chances for tension and drama of any available character. The second Robin who was believed to be murdered by the Joker, Jason eventually returned with a grudge against Batman for not avenging his death by killing the Joker. Taking on the mantle of "The Red Hood" he attempted to force Batman to kill the Joker. He'd make for an unpredictable and volatile addition to the next Arkham-verse game.
8. Maxie Zeus
A mob boss who believes himself to be the reincarnated Greek God Zeus, Maxie is one of the more colorfully offbeat villains in Batman's rogues gallery. His preference for electrical based weapons would make for some interesting level design and an interesting boss fight. His presence has already been hinted at with his cell being visible in Arkham Asylum and his night club Olympus showing up in Arkham City, so hopefully that's a sign that Rock Steady is planning to make use of him.
9. The Ventriloquist
Another colorful villain that has been hinted at in previous games but not made a full appearance is The Ventriloquist. His puppet Scarface is seen multiple times in both games, but Arnold Wesker himself has yet to make an appearance. The potential for a unique boss fight against a man and his puppet, is something we hope to see Rock Steady explore.
10. The Clock King
Although Temple Fugate only appeared in two episodes of Batman: The Animated Series, they were two of the most memorable episodes. Fugate's obsession with clocks and timing would offer a chance for some frustratingly brilliant puzzle based level design.
Characters We want To See More Of
In addition to the above characters, here's a few who have already shown up that could use some more screen time.
11. Calendar Man On The Loose
Tucked away in the basement of the Gotham Courthouse Julian Day sits in a cell doing very little with his time. If however, he's approached when the system clock on your console or PC is set to certain holidays (one for each month of the year) Julian will confess a murder to Batman. After hearing all 12 confessions and returning to his cell, the player will see that Day has escaped and left one of Two-Face's dead henchmen in his place. Hopefully this well hidden easter egg is setting up a bigger crime spree for Batman to foil in the next game.
12. Oracle Actually On Screen
While her voice has been prominently featured in both games, Barbara Gordon a.k.a. Oracle hasn't actually been on screen yet. Hopefully the next game will players a chance to actually see her on screen.