I discovered her when I was fourteen. She and Ivy Valentine from scIV were and still are hot shit for me.
It's a shame neither are coming back. Valentine died when SCV tanked and the whole series was shelved, and Peeg would never survive in a post-Miss Marvel comics world. Don't get me wrong, I like Miss Marvel and for the most part I like the new direction comics are taking. But DC and Marvel are both super reactionary, and would never give a chance for explorative or clever writing to say, explain the chest window, if the main character looks like a sex symbol. They'd be too worried about being accused of sexism because although they profit from shit like Miss Marvel they don't understand the people who buy her books.
As for the window itself, my personal headcanon is "For a long time I was uncomfortable with my body, especially my boobs, because people kept using it to sexualise me. I would save a bus full of people and the news would instead talk about my tits, so embracing the way I look is affirming for me."
You could even give her a curvier, pudgier look and move away from the standard superheroine bod. She'd still have giant boobs, just with a stocky body-type you'd expect a real woman with a big rack to have. The costume mkes even more sense in that regard - "people alternate between making jokes about my tits and mocking me for being chubby and not looking like a victoria's secret model, so I'm going to embrace the way I look with a skimpy outfit,a one-piece bathing suit with a chest-hole, because it's empowering for me."
But I doubt DC would write something like that. They'll put out issues about "sex-positive" Starfire who fucks people and then pretends not to remember them but they'd never try anything above.