Mary Sue, Marty Stu

[Tonus]

I don't read comics so others might know better than I do about this. It seems to me that Marvel makes more of an effort to make their characters three dimensional, complete with power limitations, tragic mistakes or personality flaws, the surrounding characters act with their own motivations rather than just fawn all over the protagonist.

That's correct. One of the things that turned Marvel from just another comics company to the most popular publisher in the US was that Lee and Kirby's heroes spent some of their time dealing with the sort of seemingly mundane stuff that ordinary people did. The Fantastic Four bickered amongst themselves, but also nearly got kicked out of their building when the rent was past due(!!!). Tony Stark (Iron-Man) dealt with alcoholism. Peter Parker (Spider-Man) dealt with being a teenager!

Meanwhile, DC's superheroes mostly had to deal with the fact that they were so goddamn awesome all the time.

One of the things that made Alan Moore's Watchmen such a seminal work is that he presents his heroes as regular people, with their good days and bad days, with their flaws and imperfections and their ability to be brilliant one moment and utterly stupid the next. Rorschach winds up defining the modern anti-hero: a bitter and angry loner who insists on seeing his world through a black/white neo-conservative filter, never able to figure out why things have gone so wrong, but determined to fight to the very last. Popular, but not the sort of person people would actually emulate.