It wont be. This can be for one specific scenario in the movie. I doubt they wear those the entire time.It's probable that this isn't their only designs for the film.
I think they look good.....but, I agree, I miss the Strong world Business suits.
Also Zoro looks like an assh*le, wtf is with those out of place gloves. And Nami decided to say **** it to the whole spy theme I'll just wear a bra like always.