I’ve had thoughts about this for a while, and my conclusion is that the problem with Mary Sues isn’t what people actually say it is.

The problem with characters that are hyper competent, likable to everyone in the text, perfect in every way, is that we’re somewhat hardwired to hate those people. Jealousy, finding them boring, hating them for the effect they have on the story, whatever you like. Characters like that are often even specifically used as villains for that reason.

The way to balance hyper competence is with some genuinely huge flaws. Light is an egomaniac who is constantly nearly being caught out. Iron man is a narcissist with a huge drinking problem and emotionally unstable. Superman is a huge dork with confidence issues. Spiderman is lower class.

There’s a kind of karmic balance that’s struck, therefore it works better in people’s minds for a number of reasons. It helps humanize them, it better matches people’s lives experience, it makes the character pop.

Here we get to the main problem: Writers are phenomenally bad at writing women. It’s cultural at this point. Women are rarely if ever depicted with internal struggles, ideals, or even flaws beyond superficial ones. If they lack that depth to achieve the aforementioned karmic balance, they can’t become well rounded characters. You essentially nailed on a power fantasy to a wooden board. I would argue that weakness is where the huge systemic sexism comes in, but I digress.

Case in point, my understanding is in the new superman movie his cousin shows up, pretty much the same power set, and she’s just a huge mess. I’ve not seen an iota of Mary Sue accusation about that character, because she’s balanced in that way. Wonder woman might be a better example as a main character, because she has concrete flaws, and they actively have consequences in the story. Her inability to navigate the world and it’s rules is both a blessing and a curse for her, and the story reflects that. Harley Quinn gets away with so much, but people don’t mind because she’s a nutcase.

Something like Rey, not only does she not really have flaws, she barely has a character. It’s not entirely one dimensional, but poor Daisy ain’t got much to work with here. Because the story is suggesting we should like and root for her, but not giving us much to actually humanize or relate to her, we tend to reject that mentally, and it often bothers us that the story insists that she’s the real deal.

Korra from LoK is a slightly different case, where the character has flaws, but the story often fails to honour their consequences. If she’s constantly screwing up, but never really being punished for it, if feels fake, like the story is cheating, and people hate that as well. I personally think it might also have something to do with how the show structures her emotional growth through the series, but I don’t want to get down that rabbit hole.

I think there’s an ease of writing men that comes with practice, as a society. Just like stories have the heroes journey, artists have colour theory, and character writers can write flawed men. There’s a whole world of good male characters to draw inspiration from. I just don’t think we’ve gotten there with women yet.