So everybody has something unique about their characters that makes them special, right? Well, how many times have you heard the same thing? bored spoiled princess, tough girl, lone hero, suddenly-orphaned hero of the day, superhero who's family/friends/planet are dead/destroyed, whatever. We've heard it all before, haven't we? So why are there still ideas that are somewhat unique that we never see?
Color-blindness. It's a common enough occurrence (and not just a genetic trait to men, only certain kinds are strictly-male.)and a genuine problem for some. One can still work around it, while it still hampers some.
Light-sensitivity. It's a good reason for the good guy to wear sunglasses at night without being that "dark and tormented soul" we keep hearing about. It's a serious problem that takes serious working around, so why do people opt instead for having a dark and tormented past or being entirely blind?
Inability to feel pain. Do people not realize just how big an issue that is? It may be difficult to work around, but not being able to feel pain can be a serious problem for a character to try to work with.
Broken Bones. It seems obvious, but I rarely see any character who keeps a cast for anywhere near the amount of time a person with a broken bone should keep a cast on. It happens occasionally in cartoons that someone gets a bone broken and spends all of one episode in a cast, but I don't think I have ever seen it last for any length of time. A pity, since it is something one would need to work around. I see how it could only work for about an episode in a cartoon, but it's not often someone simply breaks a bone in a book. It's either a severe injury, or it's shrugged off after a bit. Kind of a pity, really.
A real disease. I'm just mentioning this because usually if some character has a disease, it's typically one that was made up. After a while I start to wonder who has more diseases: Reality, or the land of fiction.
War wounds that are still open. War wounds almost always seem to be old scars. What if the fight wasn't that long ago? It'd be more interesting to see the pain an infected war wound causes than seeing the battle scars. Scars tell a story, open wounds show one.
Just a few of many ideas that'd be nice to see more of once in a while.