I've been gathering image reference in case I decide to do one of the characters, but I want to see the movie first. I don't like to cosplay a character unless I've at least somewhat familiar with the material. Otherwise I risk spending dozens of hours on something just because it has cool style, only to later discover the character is a total twit that I would never want to identify with.
From the trailer it looks like a great visual spectacle and I don't doubt it's going to be the next big trend for cosplay. However, it looks like the film could also be one of those movies that's really a T&A fest masquerading as some girl power crap. Basically an excuse put a bunch of young women in tight scanty clothing, then call it empowering because they shoot guns. More of the male
fantasy idea of what female fantasy is -- where no matter how poor and abused the women are they somehow always find resources to have immaculately styled hair and tons of eye makeup while scrubbing the floor.
I really hope it's a good, fun movie and not something like Tomb Raider with better special effects.
edit: doh! forgot to add... from the image references I've seen the Sucker Punch characters are definitely ADVANCED costumes. Like very expensive materials, lots of leather work and vintage materials required, lots and lots of time. In other words, with the exception of Baby Doll I don't think the movie is going to be accessible to most cosplayers due to the time, materials and skill level. So we're probably going to see a lot of very bad closet cosplay for Sucker Punch, with a few advanced people really doing it justice. My prediction.