Mark Waid has said that Irredeemable is about someone who became a superhero without being psychologically capable of being one. In the case of the Plutonian it is clear that he is much more reliant on others' opinions of him than he should be. This is one of the many causes that drives him to be a Complete Monster and though you can see the origins in his earlier life it is clear that this is the immediate cause of his madness.
Note also how this madness is expressed. For all his superpowers and mind-games and cunning, the Plutonian's acts of vengeance in many cases typically resemble nothing as much a childish temper-tantrum or the actions of a schoolyard bully writ-large and powered by the strength and abilities of Superman. Essentially, he breaks things and hurts people. He wants people to like him, but when they don't react like he wants them to he lashes out. He wants respect, but like a schoolyard bully if he can't get it any other way he'll get it through fear. As well as his inspiration's moral centre, then, the Plutonian also lacks Superman's essential maturity.
This can apply to other Characters as well. Look at the Batman Expy The Inferno. He was killed off panel by the Plutonian while proclaiming his disbelief that his friend would turn on him. This is a move that is very unlike the Batman that we know as that is the kind of character that almost expects the people around him to betray him. That is how he is able to function and survive as a superhero, if not as a human being. The Inferno, though barely touched upon, shows a good picture of what Batman has to sacrifice to be the Badass Normal that he is. He had to sacrifice trust and friendship.
This also is touched on with Quibit, an Expy of The Doctor. It is shown that he is unable to bring himself to actively try and kill the Plutonian and is still looking for a way to redeem him. Perhaps he never read the title of the comic. This does create an interesting contrast with The Doctor and The Master, where it is clear that The Master was at one point a very good friend of the Doctor he now has turned himself into a villain that, even though it may pain the Doctor, must be stopped.
With this we can see that the true intention of this comic is taking these characters and removing the basic psychological needs that they need to survive that we as readers often take for granted. In this way the comic is almost a deconstructive celebration of these characters by showing us ways in which they were great that may have never occurred to us.