the new midnight blue costume could be an issue with lighting/saturation tricks, or it could be a part of the story. the Avengers uniform was intended to be function-over-form, being realistically functional body armor and tactical slings. This could be an extension of that, moving to a more effective urban-camo color than the bright primary blues and whites and reds of the traditional Cap suit. in that way it would serve the story-line of Steve trying to fit in with the world of the twenty-first century and his duties with Shield. As CG said, there is likely a moment in the film where he says "pancake this stuff" and goes back to the more traditional stars and stripes ensemble.
that sort of complex visual story telling is definitely in line with what Favereux did with Stark in all the Ironman movies where in each armor was subtly more advanced and purposeful than its predecessor, and likewise Batman Begins to The Dark Knight made the suit a part of the story, bringing up each iterations' advances and drawbacks.
