Also,I'd love to see the Riddler not re-worked as a Saw-like killer or an FBI agent but rather an arrogant,obsessive compulsive mastermind "catch me if you can" thief leaving clues/riddles behind to his temperary whereabouts and next schemes.
Isn't that how he is already?
If I had to work the Riddler into a movie, I would make him an already established criminal, obviously. To begin with, he would be on the FBI's radar, going from town to city just causing as much trouble as he possibly can for those who are hunting him. A thief, a con-artist, etc. Testing everyone from sherrifs, detectives and agents to track down and stop him from succeeding in his next crime. Obviously to show he is the best and cause great shame to those who failed to capture him. Edward, after hearing about Batman, decides to end his criminal career with a final challenge against 'The World's Greatest Detective'. He fails, and is captured by Batman.
But Edward escapes custordy, and fakes his death (sort of like the ending from his first comic appearance). Months pass, and he later emerges as The Riddler, after creating his deadly revenge challenge for Batman, determined to defeat the Dark Knight once and for all...
I would also rework his backstory a little bit. Saying he was educated at all the top universities, Harvard, Yale, etc. Gifted in many feats. Taking interest in writing (where his gift for creating riddles comes from) and was the champion of chess. Playing games and solving puzzles were among his favourite things as a child. His control freak father is the cause of Edward's OCD, forcing him to enter competitions and win no matter what it took. As a boy, if Edward failed to come first place, he received a beating for failure. So whenever opportunities again like that would come around, Edward cheated, fearing the wrath of his father. He received nothing but praise from that day forward. If Edward couldn't win, he would cheat. This filled him with over-confidence, and arrogance. Eventually losing sight if what cheating actually was, it was just a way for him to win.
After finishing his studies and graduating, he went to work for a top security development company. Eventually becoming the head of research and development. Knowing the ins and outs of latest technology in security systems, from to bank alarms, to the police supercomputer.
But of course, Edward's mental health began to deteriorate, due to obsessivley over-working. He was soon on medication, after being diagnosed with OCD. He was deemed a liability for the company, and was terminated. This lead him into a deep depression. Not interested in getting another job, and becoming angrily bitter and frustrated. He remembered his childhood, the feeling of winning and spitting on the face of the loser, surfaced within him. The feeling of his father's fist smashing into him for failure surfaced within him. Edward's life soon spiralled into crime.
That's how I would do it
