Wonder Woman fans typically either don't want her in pants, or don't care either way. The skirt has always been the best compromise as it fits the character's mythology and looks great. I do wish they'd settle on making it around knee length, though.
They've tried a couple of times. Her DCYou suit had pants, but people didn't respond well to it overall so they went back to her Justice League suit. And then there was the jacket redesign, which I really liked but most people HATED.
People prefer Wondy sans pants, I guess. The battle skirt is a good look.
The jacket design is a fine design on its own. The problem is it doesn't really fit Diana. It loses much of the iconography and has little roots in her Greek origin. If you put the same outfit on Donna or Cassie, people probably would have been more receptive.
You have to also keep in mind that the jacket redesign was just one of many massive overhauls to Wonder Woman's look and also accompanied a huge shift in her lore/status quo. If there's anything Wonder Woman fans are tired of, it's DC constantly trying to "fix" the character.