Attack on titan fanfics mistakes

Character

I have read lots of aot fanfiction, specifically the levi department, and one noting similarity that too many of these have is...

That they have basically the same personality and uniqueness as who they're being paired with.

A lot of the aot fanfics I've read have had their parents killed and they live all alone they're so unhappy pls save them.

And this leads them to be super stone cold and they let nobody in oh my god please they're so strong and they totally surpass levi but they're still not humanities strongest.

And holy crap wowsers they can kill 60 titans in 50 minutes that like oh my geebers a lot.

But they're still totally not humanities strongest or anything.

But don't go near them because they'll kick your butt!

Yeah... Please don't make your character kuundere or something. Yeah that like.. No.

No Mary Sues please.

Also with eren the character is almost always a titan shifted and wants to avenge their parents from the titans because they killed them at the attack.

Like, come on people. Be more original.