First appeareance Detective Comics #140 Oct. 1948
With the exception of Frank Gorshin's balls out manical interpetation of the Silver-Age character in the '60's Batman TV series and film, The Riddler has consistantly been portrayed as an ultimately pitiful villian.
Indeed, he fails to rate in the top 50 comic book villians of all time, coming in at number 59. Beat out by such lesser knowns as Hobgoblin, Sebastian Straw, Metallo, and even Cassanova Nova for the 50th spot.
But, why isn't he more popular? He's well known enough, famous enough. Why isn't he right up there with the Joker?
So, let's ask the question Nygma might ask himself. Why don't people like him?
Part of the answer lies in Edward Nygma's wearing his insecurities on his sleeve. He knows he's no match for Batman, despite his false bravado. He'd like to be, he feels he's smart enough to be, inventive enough to be an equal with the Dark Knight, if not the Detective's superior. It's Riddler's multitude of neurotic tendencies that ultimately do him in.
When pitted against The Batman, The Riddler is simply playing out of his league. It's his very calling card, the riddles, which always do him in. And, he is helpless to stop leaving them. It's as if he paints a giant bullseye on his own green suited butt.
He's doomed by his own inadequacies.
And, readers see this. It repels. The Riddler reminds us of our own failings and negates an empathy that might otherwise be felt for him.
Curiously, Gorshin chose to discard this weakness in his interpetation of the character and nearly fifty years later stands as the highwater mark of The Riddler's popularity.
To put it another way, Gorshin did for Riddler what Ledger did for The Joker.
ACL's Riddler is currently on extended hiatus and is therefore unavailable for roleplay.