Yeah, I'm doing an actual article about character design. I know, right? Crazy. It'll be over quick though.
This is Kei Nagase from Ace Combat 5. As you might be able to tell from her design and also the fact that she's from a game called "Ace Combat", she's a fighter pilot. I bring her up in order to contrast her with a slightly different character: her original incarnation, from the game's concept art. The two characters are basically the same from a design standpoint. They have slender builds and short black hair. They're wearing flightsuits. For most intents and purposes, they are the same. So why bring them up?
Because when I hear people talking about character design, one thing I hear a lot is people defending big, sweeping design decisions. Those kinds of artists feel the need to make overwrought designs and then defend their exaggerations as being necessary to let the audience understand the character. They don't trust the audience to pick up on subtlety. So you end up with a lot of overblown characters wearing ridiculous outfits, and they get defended because people feel they have to be like that.
Look at those two designs again. They're the same, but they're not. They have different hair, different eyes, a different mood, a different feel. Their eyes, their facial expressions, their stance. All these little things. You could put those two characters side-by-side and play them off as totally different people, and I'd bet that audiences would accept it.
The "finished product" Kei Nagase is more taciturn, somber, and withdrawn. She doesn't really have a lot of emotion to her, and, as a result, "not being emotional" becomes a distinct part of her character. Obviously I've only given you a single CG model to work with, but rest assured, it's a theme that carries through - for example, here, here and here. While there's moments of intensity with her character, she's very rarely expressive. It's not that she's glassy-eyed and poorly rendered, but rather, you get the feeling that she's not totally there, like she's not really paying attention. She's a perpetual daydreamer. It's a thing.
The "original model" Kei Nagase is clearly more energetic, even though you don't have a line of dialogue to work with, or a single snippet of voice acting. Her hairstyle has more of a "punk" feel to it, even though the only real difference is a few wayward strands. Her eyes feel more intense, and convey assertiveness, in contrast to the "finished product's" detached nature. Even in the pose where she's reading her book, the original seems more involved in the action, more engaged, whereas the finished product seems lost in the work.
This isn't to say that one design is better than the other - far from it. The point of this exercise is to show that, even if you have a huge number of restrictions on your design, you can still make characters that are distinct and memorable and whose designs say something about them. Even if they're wearing a standard-issue flight suit or "realistic" armor or whatever else, you can find ways to make them people. And we're just talking about visual design; that's not even getting into the extra layers of writing and voicework and all that. So don't tell me you can't do it, because you can. Subtlety's not that bad. Realism helps. It's a thing. Pick up an anatomy book while you're at it.