Yeah only takes a couple of hits to kill someone, but obviously it applies to the enemy too. Because of it I find players are not sprinting everywhere, they are taking their time using cover and actually waiting for teammates to help them out. Also, no crosshairs on hardcore mode, so in normal mode you really should concentrate on keeping that crosshair at head height all the time, then when you play hardcore it should be second nature to be always aiming at the enemies' heads. As Fletch said, teamwork is needed more in HC mode.
Does it actually take less bullets to kill someone in hardcore mode? I wish there was a mode to remove all screen clutter. Good tip about the suppressor though