Some of you guys have done a good job of listing interesting characters not in the game. There's at least 10 characters minimum that should be included before yet ANOTHER batverse/bat family member. Bats has a quarter of the roster and almost half the stages. Even the same stage twice "in day and night" just to remind you how ever present he is. Enough is enough way before enough was enough.
Makes me wonder if they should just make an off-shoot Batman game. C'mon we already got Batman, Batgirl, Nightwing, The Joker, Bane and Harley Quinn. I could see them adding the likes of Red Robin, Talia, Ra's al-Ghul, Man Bat, Clayface, Mr. Freeze, Batwoman and the list goes on and on.
I like Red Hood, he is pretty popular now but he's more of an anti-hero, not a villain as someone above stated. But he's still a relatively new character. When yes we have many others to choose from that get nothing, no credit at all that I would love to have like the Charleston characters of Captain Atom and The Question. The Creeper (not stupid mystical version), Etrigan, The Phantom Stranger, The Spectre, Jonah Hex, Wild Cat, Orion and Dead Man.
One thing they should do regardless is every hero should have their villain. Bats got Joker and Supes got Lex and so on. But a few are still missing
Aquaman - give us Ocean Master or Black Manta
The Flash - Captain Cold, Mirror Master, The Trickster, Captain Boomerang, Professor Zoom or Gorilla Grodd
And on and on, then they should take this into consideration for Injustice 2