This was a nice feature in Day of Infamy where your screen would start to blot out in monochrome or red opacity when on the verge of death after being shot at or injured. I'd like to see this return in Sandstorm so we can gauge how injured we are after a firefight... and if resupplying actually heals us or not.
@musicnote DOI also has automatic weapons and can be fast paced with enough players. I mention this because you can still get shot in the limbs multiple times or center mass with body armor (depending on caliber) which will drain your health. I mostly want this effect to handicap injured players because they usually wouldn't/shouldn't be running and gunning if shot in the leg or injured.