Jack Kirby was the master of fantastic costume design. While many of his more extreme designs could never work in real life, it doesn't matter; they were the epitome of "sense of wonder" and gave characters a grandness and a strangeness befitting the stories he told. And his level of craftsmanship and sheer enjoyment of the form that meant that even character like Knorda, the normal sized queen of the hill giants is depicted in an individual detailed costume when she only ever appeared(1) in 4 panels, two of which were a head shot and a back view.
So I have to assume that Jack was just having an off day when he created Beautiful Dreamer.
Beautiful Dreamer is the only female member of The Forever People, and one of only two heroines(2) in the entire New Gods saga(3), so what could have possibly possessed him to dress her in an old sack? Had he just run a bit dry after creating so many new characters for the epic? And if so why was she stuck with the rag for so long? You might say it was part of the whole hippy vibe that the Forever People have going, except that all of the other members of the group are dressed with typical Kirby flair.
Beautiful Dreamer continues to wear the sack, which appears to be slowly disintegrating as the series progresses, until issue #9, when kindly old Trixie Macgruder gives her a new dress. We then get Beautiful Dreamer's only comment on her choice in clothes "The body is merely a three-dimensional identification vehicle! It's our "total" selves that beautify us!"
No, I don't understand why that means she should wear a sack, either. But when she finds the dress Trixie gives her to be too old fashioned for her "total self", Serifan zaps it with a cosmic cartridge into a much more fashionable little number with a lot of fringes, and matching boots. Sadly, this "atomically re-shifted" form seems to be a little unstable, because by issue #11 it has gone from strawberry red and white to the orange of her old sack. Or perhaps the colourist wasn't paying attention and forgot she had a new outfit.
1. Yes, I know she turned up again as an important character in the Domination Factor miniseries, but that was 35 years later. And they still never explained how the giants came to have a queen who was normal human size.
2. The other being Big Barda, obviously. Shame on you if you didn't know that one. And no, for the purposes of this entry I'm not counting the Female Furies who were briefly on the good guys' side.
3. New Gods, Forever People, Mister Miracle, and Jimmy Olsen.