I don't even know how can a story be good if it has no interesting characters. Out of every comic, TV series or movie that I like, I can't think of any where the whole point of the story isn't one or more characters' experiences, feelings, development or such. Characters are not the reason why I start watching or reading something, but they're the ONLY reason I stay. And of course I can say the same thing about writing stories. If I start writing about a character, and I suddenly feel like I stopped liking it, I keep changing the character until I like it. Are the most important characters in that story not good or interesting enough to me? Then there's no story to listen to, or tell.
But you have to bear in mind that a character is not just their looks and personality. A character can (or must, even) also be an idea of a life; a story in themselves. The way I think of it is... Am I just a human that looks this way and behaves that way, or am I also, and more importantly, a life, a memory, and a story in myself? My life is who and what I am, and (ideally) a character is also their story/life/goal/role first, and their other atributes second, even if those are directly related.
My process of creating characters goes more or less like this when the first idea is a sketch (actual example):
I wanted to make a vigilante. I sketched what came to mind first: A blonde, goodlooking, mature, responsible and well intended ex-cop with a big sense of honor and justice but with obvious anger issues and merciless attitude towards criminals.
That didn't last long because it was bland and uninspired. I started digging and realized that I didn't like the idea (done too many times, not that special, it's literally the Punisher, whatever). Then I took that same character and gave them another twist. What if he's not honorable or just, but he believes he is because he has a severe case of misophobia and, coupled with some other external factors, he thinks dirty=evil and clean=good? I then came to like this absurd, nearly insane version of the same character more, then changed his personality to fit his past, his beliefs and his goals, and then changed his appearance to suit all of that. More specifically, I made him wear mostly white cotton clothes and perfectly clean and combed white hair, along with a skinny and weak body because he hates sweat and doesn't do any kind of exercise, eats very little food in order to have to poop less often, and doesn't eat meat because those are just rotting corpses (as opposed to muscular blondie with black leather clothes). Then, I thought "how can he be a vigilante if he's physically weak"? Well, maybe he has psychic powers or sci-fi gadgets that do all the job for him! Maybe somethint that resembles a vacuum cleaner. Then I decided that I would no longer make this character serious, and would turn his story into a comedy and his universe into something he made sense in, such as a very dirty neighborhood he wants to purify, a lot of fantasy elements that could explain his powers/gadgets and a development that will make him learn that clean doesn't equal good. Yes, it's similar to the likes of batman or the punisher, but with a personal little twist that makes him unique enough to don't feel like the blonde version of either.
I like asking a lot of questions about any given character I design if I'm interested in their story, and go through all of those steps to make it more interesting.
Well this is like, the polar opposite of what I just said lol. Or maybe you're saying the same thing I did in another way, from another POV? Not sure.