Mackie was great in The Hurt Lcoker, and personally I loved him in 8 Mile.
Great to see Falcon and Cap partnership on screen, one of my favorite duos in comics. I think a mix of his 616/Ult. costume would work, its a bit boring to see just gray on black, i dont mind them giving his outfit a bit of color. If your standing next to the man in red, white, and blue, i think you can make anything work visually.