It sounds like Hawkeye has a lot more to do in this film than in the first one, where he was simply brainwashed for most of it. The new outfit seems to emulate that of the comic book version of Hawkeye (until a recent style update).
About the actual film itself, Iron Man himself had this to say:
"This one is a very ambitious sequel," Robert Downey Jr. said this week. "If you read it, it's dense, it's smart. Joss [Whedon] is a really smart guy. My 2-year-old is crazy about Hawkeye, and I think Jeremy [Renner] has a lot to do with the plot. There's always so many plates to spin to get these things half-right, and I'm really excited about this one."
Enjoy these possible spoiler-filled shots of Hawkeye, Scarlet Witch, and Quicksilver in action against what appears to be an Ultron drone (or possible stand-in for Ultron himself).