I thought of another one. Poison Ivy could be a botanist who loses it and starts using plant based toxins to commit crimes and/or targets plant related locations.
Poison Ivy: Botanist turned eco-terrorist with a thing for honey traps and exotic poisons with no known antidotes. Probably targeting Bruce's industrialist buddies (or Wayne Enterprises in general) for their involment in oil spills, logging, pesticides and toxic waste dumping. A genuinely stunning beauty who uses her looks to get close to powerful men and dose them with a slow acting contact poison.
Better yet give her martial arts talent. Make her Vietnamese. And change her name to "Cheshire."
Actually, given the pop cultural abyss that was B+R, that's maybe not
the worst idea.
But it reminds me, Deadshot would work out fine for a Nolan film.
The Riddler's problem in a movie is the same as my impression of most of his comics: he's fun enough, but all he can do is offer a generic Batman case. For a $3 comic, that's okay; for a theatrical film, a generic Batman case is insufficient.