That's the point: if it's not your character, you should have respect for it. There's a reason why it's taboo. The pictures painted of the characters' character is important to the story (else it goes entirely unmentioned), so by trying to change peoples' view of a character, you're not just subverting the character but the story as well, and consequently the lessons and issues in the stories. If Jesus' story is about redemption from changing your ways and trying to undo what you've done to others, and that people whom are "perfect" will then forgive you and that you're not eternally judged by nature/society/God/whatever as criminal and evil, then there is no redemption if picture of the "perfect people" changes to "flawed people." The story has no meaning of being able to overcome your weaknesses if you don't have something strong to compare yourself to, or to judge you in a positive (redemptive) light.

That's why characters are what they are: so you can compare yourself to them, to see how you fit in the overarching narrative. Ash Ketchum of pokemon, uses electric types against ground types, but somehow he overcomes. He is so pitiful and pathetic that he is given his rewards. Meanwhile, he idolizes Red, his hero, whom happens to be YOU, who is far more competent than him.

In dragon ball, we have Gokuu, who is so innocent that he has to feel the crotches of people to identify them as either male or female, because he doesn't necessarily judge people's fighting ability, strength, threat-level, etc based on their gender (and presumably race and such). No one can ride the cloud, except him and a few special exceptions, because they are not innocent, and they judge others on those attributes the he does not. Meanwhile, he's always the hero of the show, the strongest of all, because he works hard at what he does, instead of trying to take advantage of others because of their social status resulting from their race, gender, etc.

Then we have JC Denton, who does what he feels is right, but in the end he is in conflict between the ideals of different belief systems. Technology has helped mankind alot, but it also provides a method of totalitarian control, so if you side with the tong, there are no leaders, and anarchy can reign. On the other hand, you can be an open dictator, but benevolent, and you will be the judge of what is right and what is wrong, but in doing so everyone will know who to target if they want to take your throne. Or, you can rule from the shadows, be a half-dictator hiding from sight, thus you don't have direct control over every aspect, but you also become much like those whom you were fighting to overthrow: the shadow government, that is both inept at making good things happen, but not so inept that mob rule occurs. In the end, all 3 are corruptible, and there was even a 4th potential ending.

In Morrowind, you are the reincarnation of Saint Indoril Nerevar, and while you have your own character and decisions to make, you are the reincarnation of someone else with much, much more history, and this is to give gravity and meaning to your avatar's choices and situation. Do you believe the tribune murdered you, or do you believe that they did not? Do you forgive them for what they did to you in a past life, if you believe they murdered you, or do you not? It determines how Indoril Nerevar is painted: was he really a saint fighting for freedom and betterment of the people of the world, was he fighting just for his own power, or was he just a toy of someone else? The lesson is, if you cannot forgive people (vivec) for what they do to you, you'll have a harder time reaching for your goals (ending the blight), but you also have that choice and can still do it without sacrificing your values. You're meant to make both decisions, and you were originally able to sacrifice the whole world for your petty revenge against the tribunal (via joining Dagoth Ur, who became the devil to stay loyal to you), and you'd be forced to live with those choices as you continued after the main storyline.

For the story to maintain it's metaphors and lessons, the story must keep the value, backstore, and meaning of it's individual characters. By subverting a character, you subvert the story, and the lessons of the story. If you want to paint a different lesson, you need to create a new character. Characters throughout the elder scrolls that remain throughout the series have meanings that don't depend on their individual character (ever notice no one ever really states reliably if any particular daedra is good or bad? The fact that their character is ambiguous is important to the bigger overall narrative of TES, which is the constant conflict of those who favor Anu [order/tyranny] and those who favor Padomay [chaos/freedom], and those who are stuck trying to keep the two in balance, trying to stay good, rather than evil). You want to keep your most important characters in a very structured frame, to force people to see the lessons you want them to see, which is usually some story about taking chaos (pure anarchy and freedom) and bringing it into order (pure tyranny/justice/safety), or using chaos to escape the evil of tyrannical order, or using order to punish the evil hiding in chaos. It's almost always a story that's somehow about keeping freedom and justice in a respectable balance. I'm not particularly familiar with Hades, to be honest, but we do know that Disney's not exactly giving us the right picture of his original character.