My take is that he's seething with rage at being disenfranchised from birth; his lack of emotional development and mental illness increases his sense of isolation to create a murderous feedback loop. His 'exposure' of hypocrisy and lies isn't based on morality so much as resentment that they get things he does not.
Yeah, I guess that's what I was getting at. I remember his telling of Bruce looking down from his golden tower and being angry people felt sad for the rich kid. I think that's a great basis to make someone bad. Now, what does he do with his "badness" to enrich himself and make his life better? That is what is lacking in Riddler. He's just "lashing out" much like Columbine kids, and thousands of others since, but he should be smarter... he should be able to lash out while also bettering himself. That's my point about not having the villain have too noble of a cause -- his "plan" still needs to have a dark, selfish, self-serving side.
Riddler's endgame was just going to jail. That's not too smart.