Well, I could turn that around, and ask why she is losing anything by wearing less than her teamates? Why as a character with the power of the gods, does she have to cover everything like Batman? Part of their power is the perception of other people around them...hiding her in plain sight hides her power. Batman gets his power from looking like a big scary demon who swoops down in the shadows, and has to wear body armor because he is a normal human with human weaknesses.
Diana shines like a beacon. That beacon would work best in her iconic suit. No one really remembers her in the original skirt, she has, IN THE PUBLIC EYE, been presented in the shorts/"bathing suit" version. Not a thong, nor a skirt...
I don't hate skirts per se, but it gets into silly season when I see skirts down to her knees, as if she should be ashamed of herself, and stuff that covers her backside while riding up her thighs much higher than what the shorts version would cover. I also think skirts will be sexier than you may have thought it through due to the "upskirt" effect.
I don't hate pants either, and I like the Chiang version with pants as something I would love to have the body type to wear. But I love an entrance, let her be iconic. It was good enough for my mom, for the feminists who run the school where my niece attends, it was good enough for me...but I'm not good enough.