So... starburst is a medallion, which she activates, it goes to her chest and the costume then forms around her?

t: That was my first thought as well. But then I would totally pay to see a movie with Carol shouting out "Kree Cosmic Power!" and getting her own transformation scene complete with sparkle background.
I like the idea, although I agree it should be something smaller, maybe something she can pin on the side of a jacket collar. What about the pin on her sash? Visually it's has a very "heroic costume change" feel to costume sort of "unravel" from the brooch, plus it would be a great actual transformation scene when Carol first suits up. Plus I'm sure they could do something with the effects that would look quite alien.
I've always liked the idea of it being a kree battle suit that Carol adopts due to Mar Vell, something sort of alien and that is as resistant in battle as she is (I mean, I assume any "normal" clothes would get ripped to shreds if Carol were hit with an energy blast; she can absorb them fine, but last I checked cotton just does NOT stand up to laser-gun technology - trust me kids,
do not try it at home) all which gives her a solid reason to trade in the air force uniform for a more colorful costume. Hey, who are we too judge alien fashion sensibilities? I mean, look at what we were wearing in the 80s.....
Or we cannot not. I want Carol to stand on her own. I'm already iffy on the first female hero to get her own movie needing to get her powers AND be "inspired" by a male character (none of the MCU's MALE heroes were "inspired" by others, let alone female ones, so there's that problematic element), but I can get past that. But do we really need to make her costume look like Mar-Vell's as well, no we don't. Let her stand on her own at least a little bit, not EVERYTHING needs to come from him.
Cap's was inspired by a song and dance outfit, so that's pretty embarrassing...
I totally get where you're coming from. I want Carol to be able to stand on her own in more than one way (I'm really hoping her origin/stand-alone isn't TOO tied into IW:P1 to the extent where that movie is required viewing, because I want little girls to just be able to go and see it without having to catch up on the rest of the story). However, it's difficult to separate her origin from Mar Vell without a total redo (which I wouldn't be against so long as it still worked for the character). So working under the assumption that she will still be connected to Mar Vell, I think having her costume come from a Kree battle suit makes a lot of sense. And if you set it up as a generic Kree uniform than it might come off less as her "adopting" it from a male character and more as her taking on a, well, an alien suit (perhaps it could have special properties like space-safe and just generally destruction-proof/self repairing). I could see maybe her adding the sash so that she would stand apart although I'm not sure where she would get it or the reasoning they could use there.
Basically, if audience see whole Kree troops wearing some generic form of the uniform it will look less like a male hand-me-down and more like she's using general alien tech.
That's one way to look at it, but I see it as Marvel will reach a point where they no longer have to contrive reasons for newly powered characters to suit up.
You know, I honestly don't feel any of the reasons so far have been contrived. The closest case I can think of would be Captain America's, but that scene was beautiful and I regret nothing.
I do like how they have approached costumes and identity issues so far in the MCU. I hardly believe superhero movies need to be "grounded" but I do think you need to be able to strike a nice balance in order to carry off the more unrealistic aspects. You can have colorful costumes, just have a reasoning behind them that fits the character and it's all good.