Where to begin? Well, to be honest, I have a character I created (originally inspired by a show) that has powers. Except, her powers are a bit different from "normal" perspective. You see, my original character, named Kielo, superpower centers around her wings. When I designed her, I was really inspired by the idea of an angel struggling to maintain the concept of "good". But that's another matter to discuss at a later time. Anyways, her wings. You see, although her wings appear angelic in nature, they're not just two extra limbs on her back. She actually has the ability to control the genetic makeup of her wings, which also includes her ability to change the size of them. In a sense, she can have a larger wing span to support her weight, or cute small "cupid" wings. She can even shrink them down to where she can hide them completely (they appear as a slight hump to her back). Along with this ability to change their size, she can change what the feathers are made of. For example, instead of soft feathers, she can harden them to use her wings as a shield, or sharpen them to use them as throwing daggers or such. She of course, does not have all these abilities at once, and learns how to control them in time. So here's my thing, when talking to a friend about it, they were so adamant to point out that the idea and concept is "illogical and the workings of a child's thought process". Because apparently it makes no sense that she can control the ability in her wings and not the rest of her body. In fact, to them, her entire power doesn't make any sense at all. I guess what I'm asking, is as writers (or fans of the genre) would it make any sense for this power to exist? Or am I going too far out on a limb with my concept?
The hallmark of good world building (which I would say is what this falls under) is internal consistency. You don't have to play by our world's rules (or any other particular set of rules) at all, but once you lay down your own rules you should play by those and not break them just for convenience's sake. Did you establish at one point that your character can't change their wings when they're hurt (or whatever), but then later they do exactly that just to get out of some difficult situation? Outside of the world building aspect there's the rest of the story to consider too. Even the best world building is just the starting point, and there are other things to think about. For example is your character overpowered to the point that the wing abilities let them get out of such difficult situations that there's nothing interesting for them to do? For what it's worth I thought this was a fine idea, but as with everything it depends on the execution. You could write a perfectly good story around this (I would say, contrary to your friend). My advice would be to concentrate on making it a good story. Readers are either going to understand "this is about a superhero with strange powers, I'll just have to suspend my disbelief", or they won't and no amount of catering to them will change that.
In the story she's actually afraid to use some of the capabilities of her wings because of events that happened. For example, she learns she can sharpen her feathers when facing off against a villian which ultimately costs the life of a hero she looks up to. Realizing the danger behind her abilities, she fears what she may be capable of ultimately stunting her "growth" per say. Otherwise she's not very powerful at all, at least not until she's much older (this is basically an origin story of sorts). In her current state (aka her teenage years) she mostly controls the size of her wings and their weight, aside from using them to fly. It's as she uses them more often in heroing situations that she learns what she can truly do with them
I don't see an issue with it. There are things I can do with my fingers that I can't do with my forehead. And as far as whacky fantasy plot elements go, that's not that improbable. I'd maybe solicit advice from someone other than your friend who thinks you have a "child's thought process." That sounds kind of dumb. Friends and family make useless beta readers anyway.
You could look at creatures like the blowfish. They have an elastic stomach which enables them to increase in size, which they use when they are under threat from predators. Your superhero could have this form of superpower, which allows her wings to be at one size in casual life, but change to different sizes when required. You would have to stay consistent with when and what size the wings grow to. I see nothing wrong with going from soft feathers to hard or sharp feathers. One thing I would do if you have her shooting sharp feathers, is to have it take a lot out of her, and she has to regrow those feathers and maybe this is a painful process, so she only shoots them when it is necessary. I would also use her teenage years to show her struggle with getting to control these powers.
