ahaha I am honestly fond of a few of these design cliches lol
like, undercuts YES PLEASE
pink hair protag IT'S CUTE I LIKE IT
vitiligo? yeah! IT'S GOOD! but yes definitely true that it is often used as a way to make an OC "special." but i have no doubts that people with vitiligo get bullied about their skin so that's why I like seeing it portrayed in a positive light. but it's def cheap to just give a character vitiligo just because it's "unique," like cmon, that isn't fair to people who have the condition either
also, about tumblr styles...tbh it's not so much the actual styles I'm opposed to, because more often than not they're actually really cute! it's more like I know that a "tumblr style" often signifies other cliches in stories that are really annoying I guess? which is why I sometimes avoid comics with so-called tumblr style.
but in the same way, I might avoid a manga style that looks inbred in a way (like it's based completely off other manga styles without much understanding of realism), because then I can guess that the author is full of common manga tropes and doesn't do much to put a twist to them or write with depth and meaning, beyond gimmicky premises. or a more western superhero comic style, complete with horrible awful physics-defying boobs and costumes so tight u might as well just paint a naked body. any particular "type" of style usually comes with its own set of cliches and problems. that's one reason why I don't think that artists should go looking for any particular style, but let the art fit the needs of the moment and let your personality shine through.
anyway this is getting off track. I guess basically...I don't mind the design cliches like undercuts or pastel hair, but I do mind it when it's used only as a way to make a character Cool and Special or to signify "i'm the protag!!!!!" Do it if it fits their personality I guess, or if it harmonizes their overall design