This abrupt change of direction is a shock and these outfits look like generic barbarian women from a game of Dungeons and Dragons. They completely lack the unique flavor of the Greco-Roman-inspired armor ensembles that Lindy Hemming put so much thought and historical research into creating for Wonder Woman. The Wonder Woman designs received acclaim from fans and costume fanatics alike. They were clearly inspired by the Amazon's origins in the Mediterranean and were feminine but very functional. Why mess with perfection?
Oh, right. The all-male team of directors and executive directors wanted women to fight in bikinis.
Previously, previously, previously, previously, previously, previously, previously, previously, previously, previously, previously, previously, previously, previously, previously.
Maybe as long as they're digitally airbrushing Henry Cavill's moustache out of every frame they could composite some useful armor onto those poor women?
In the filmmakers' defense, there is precedent for this fashion in the Roman strophium and subligar: http://www.ancientpages.com/2017/07/17/ancient-roman-women-wore-bikini-1400-b-c/
Sure, that explains suitable attire for beach volleyball then and now, but bikinis are clearly coming up short in defending against swords and arrows.
but you can actually look at how the Greeks depicted Amazons, eg:
http://antesdelogos.blogspot.com/2014/04/las-amazonas.html
which looks a lot like what was in the Jenkins movie. I mean, the ancient Greeks (especially the Athenians) really hated women, but they could still put them in armor in their fantasies.
This is just another incidence of lowest audience expectations, for my money best expressed in Jeff Minter's 1991 rant (which came with his Llamatron game):
The whole thing still holds up quite well IMHO.
To be somewhat fair, Snyder is at least consistent. He did that same thing with dudes in 300.