This message has been deleted.

I think there's a story in which Riddler sends clues which help Batman foil the crimes of other people. However, it turns out that Riddler had unconsciously put in clues to his own hideout, which Batman used to find him. When Riddler hears this, he realizes that he actually might be crazy. I heard another version in which Riddler also sends clues to other criminals' plans, but due to his OCD, he is forced to commit the same crime as the other criminals. The writers could have used one of these two stories or a combination of the two to make another episode which shows how messed up Riddler's mind is from being controlled by his riddles and OCD.

CHRISTIAN BALE-HEATH LEDGER
THE DARK KNIGHT
JUNE 2008

Basically, a worthwhile Riddler story is going too complex to shoehorn into a 20-minute time period. From what I heard, there were a lot of rejected Riddler scripts because they proved entirely too difficult to get down in length but remain high in quality.
Never hate your enemies. It affects your judgment.
-Michael Corleone

This message has been deleted.

I tried writing a fanfic with The Riddler but now I know why Bruce Timm and co. thought he was hard.
If I can mix Code Lyoko, Anime, Freddy, Jason, Alien, Predator, Marvel and DC together.

This message has been deleted.

Yeah we know bu that was the animated series,I wish he had at least one episode for himself here just to see what will happen

He just appeared breifly in "Over the edge" and "Judgement Day".He also appeared in the Superman episode "Knight Time".
Don't forget that he was the central villain in three episodes of Batman: The Animated Series (all of which had John Glover doing the Riddler's voice): "If You're So Smart, Why Aren't You Rich", "What is Reality", and "Riddler's Reform." He also had a cameo in "Trial", even though he had no dialogue in that episode.
Indeed, it was difficult for the writers come up with workable Riddler stories. I remember reading somewhere that one of the show's crew members admitted it.

He just appeared breifly in "Over the edge" and "Judgement Day".He also appeared in the Superman episode "Knight Time".

This message has been deleted.

Basically, the riddler is the hardest villain to use in order to make a good episode. I mean sure he is cool as a character but do you really want to see an episode full of corny riddles? That episode would probably be the worst episode of the series (ignoring "critters" of course).I guess that it was just too hard for the producers to put a riddler episode here since he is just not as good as guys like the joker and two face.