oho... ok first that comes to mind is fics where faker is very cool, like really kickass cool, but has his vulnerable moments. i absolutely love it when the strong character breaks down!
but overall, the best types of characterizations are when they are as close to "canon" as possible. this means goofy sanghyeok needs to exist in more fics!! but there also times when i love ooc characters - like in gwenisimmune's "don't blame me", where keria is a demon. i think those kinds are also cool.
oof look at my longass very vague answer... wtv ty for asking! it was fun :D