Okay Riddler is my favorite Batman villain(Joker is just a favorite villain in general), but we haven't gotten to see him DO anything in the New 52. Personally I would like them to make Riddler Joker's equal, like how dangerous he is.

How to do this? Riddler is a narcissist and people with severe narcissism are known to do things that will get them attention, anything really. If it involves doing something horrible? Then yeah they'll do it. Full list of what narcissism entails are as follows:

Reacting to criticism with anger, shame, or humiliation

Taking advantage of others to reach own goals

Exaggerating own importance, achievements, and talents

Imagining unrealistic fantasies of success, beauty, power, intelligence, or romance

Requiring constant attention be it positive or negative

Becoming jealous easily

Lacking empathy and disregarding the feelings of others

Being obsessed with self

Pursuing mainly selfish goals

Trouble keeping healthy relationships

Becoming easily hurt and rejected

Setting goals that are unrealistic

Wanting "the best" of everything

This fits Riddler to a T. Also here's something that furthers the point

A lot of these traps for the people Batman has to save in the game would definitely lead to a Saw-esque death. Which actually brings me to my next point. Currently there's been a theme going for all of Batman's villains. Make them horror themed. This really started with Rocksteady's Arkham game series, with characters like Scarecrow, Solomon Grundy, and Riddler to name a few being more or less modeled after horror movie characters. Scarecrow after Freddy Kruger, Grundy after Frankenstein(The electrical aspect and undead nature), and finally Riddler who's traps were obviously lifted right out of Saw.

What I would like to see is a story where Riddler gets an idea. People are always afraid of The Joker while they treat him with little respect. This drives Mr. Nigma to step up his game. Now this isn't to say he's not compelling on his own or to compare him to Joker, but with his narcissism Riddler wouldn't take this lying down. Picture this scene in a comic

Sure he's never done anything this bad, but if you're going for a darker more driven version then this is pretty much what you'd get. Now this isn't to say make Riddler a Jigsaw rip off, but make it where he's a VERY big threat that's pushing Batman not only mentally but physically.