The good news: DC’s new costume for Power Girl finally closes the much-maligned boob window.
The bad news: DC’s new costume for Power Girl is duller than dirt.

Especially when the internet has already given us superior interpretations along very similar lines.
Such as Joel Carroll’s take:

Or a version by Aaron Diaz of Dresden Codak:

Note that, in all three, the elements are essentially the same. White bodysuit with piping, gloves, tall boots, cape. Frankly, on paper, it’s not a terribly interesting costume - which may be part of why the boob window was such an enduring feature.
I feel like the only way to make a costume like this work is to have “fiddly bits” somewhere - just some part of it that’s got the extra detail for contrast. (I guess the best example of “fiddly bits”, just so you know where I’m coming from, is the classic Spider-Man red and blue. Imagine it without the webbing pattern. Doesn’t quite work, does it?)
For the official costume, DC has decided to go with weirdly organic-looking metallized boots and bracers, and a frankly-kind-of-off-putting off-center logo as the fiddly bits. Gold… I feel like it really doesn’t show detail extremely well.
The blue in the fan-designed costumes, though… it just pops more against the white. The fan costumes also keep callbacks to the off-center elements of the classic PG costume- with Caroll’s, it’s the classic capelet, while Diaz uses the gold belt.
This new official costume… it really does solve some of the major issues with Power Girl’s look. That’s something, at least. It just does so in the dullest way possible.