In his original Marvel Comics iteration Hawkeye has some kind of weird loincloth/skirt thing going on - a strip of fabric that covers his junk and his butthole and hangs down between his thighs. I never really 'got' it. My favorite part of Hawkeye's classic costume was always his cool pointy mask.
Well, the pointy mask is still nowhere in sight in the Marvel Cinematic Universe, but it looks like in Avengers: Age of Ultron his costume is evolving more towards that miniskirt thing. It's definitely an improvement over his Ultimates inspired pleather outfit from The Avengers! I see what they're going for here - it's approaching duster territory, giving Hawkeye more of a gunfighter look.
To be honest I care less about Hawkeye's look than his role. From what I know Age of Ultron we're going to get more Hawkeye, and get to know him more - something the character desperately needs at this point.