Disagree with blast shield - I use it and it works perfectly fine...doesn't let you get killed, but you do get damage. In hardcore, I've run through 3 IED's in a row with blast shield and it didn't kill me. Hmm...perhaps it needs a nerf rather than a buff.
Ball Vests are absolutely worthless for me. Takes 2 bullets to kill me and 30 to kill others. I think the game isn't letting me know when I'm getting shot so it seems like 2 bullets.