Don't agree with ffa mode for player count reasons, but I'm all on board for a medic kit. I think rather than one heart, just make it a three shot version of rifle. You can still kill people, but you won't be very good against the existing kits (except maybe sniper). With a medic kit, you want low damage output, but you still want kill potential. There is no way a gun that does 1 or 2 hearts per hit with a 2-3 second cooldown is gonna get you any kills.