So why can't women braid their hair (1 Peter 3:3)? Here's some historical study with a quick application for what it means for us today:
"Although Paul’s exhortation for women to “adorn themselves with modesty and humility” (1 Tim. 2:9) fits the expectations of either Greek or Roman society, the adornment of the hair “with braids and gold or with pearls” (cf. 1 Pet. 3:3) fits a new trend originating in Rome.
Greek hairstyles for women during this period were for the most part simple affairs: hair was parted in the middle, pinned simply in the back or held in place with a scarf or headband. The women of the imperial household originated new styles; by the Trajanic period they had developed into elaborate curls, braids, high wigs, pins, and hair ornaments that were quickly copied by the well-to-do through the empire: “See the tall edifice rise up on her head in serried tiers and storeys!” (Juvenal, Satire 6). One can even date representations of women by the increasing complexity of hair fashions.
If Roman styles seem a bit too far away to affect [local] fashions, consider that portraits of reigning empresses often appeared on coins minted in Ephesus and other Asian cities and that they had prominent statues in both public and private places. Portraits of provincial women from the era show that the imperial coiffures were copied in Ephesus and the other cities of Asia.
Paul’s injunction regarding elaborate hairstyles reflects the increasing influence of Rome...during the third quarter of the first century A.D. And his skeptical response to this trend was due to his judgment that simplicity and modesty in dress befit pious women rather than external extravagance. [For men, Paul’s equivalent exhortation was to avoid obsession with “body-sculpting” in gymnasia in place of piety (1 Tim. 4:8).] Furthermore, his reaction to women’s imitation of latest hairstyles is understandable since it was quite a new trend, really begun only a decade or so before, and it carried connotations of imperial luxury and the infamous licentiousness of women like Messalina and Poppaea. Today, it is the equivalent of warning Christians away from imitation of styles set by promiscuous pop singers or actresses."  (emphasis mine)
It's not about braids. It's about:
a. Making beauty and character INTERNAL (for all of us, not just women)
b. Not imitating and therefore glorifying those that are examples of a life of immodesty, vanity, excess, and promiscuity
I think "b." has a lot to say about us and our choice of fashion today.
What do you think?