I am thinking of something that might seem cool to implement in the game.
Reviving a dead person.
In real life, defibrilators are used on fresh dead persons, yes?
So let's try to use this to enhance the gameplay.
So my ideea is,there is a "You are dead" time clock.for example you can stay in the "You are dead" screen for 5 minutes, that's the interval that a player(friend) can come and revive you with the defibrilator,of course you can do a respawn in that period of time if you know you don't have a chance for reviving.
But, there is a but.Maybe you're blood level is too low,so in that 5 minute period you're friend can administer you a blood/saline bag that will partially raise your blood level,then use the defib to revive,after bandaging you.Or if he tries to revive you,and your blood level is too low,you respawn unconcious,so that player has to do a blood/saline transfusion fast.meaning if he doesn't have one bag,he has to find one fast.
That feature would be great to help out the "medics" of the game in my opinion.
When you revived,you start from health level 100, so you get another zombie hit/bullet "You are dead".
And to escape the exploit of this thing,meaning that you can't just stay there,and always revive like every 1 minute,you can be revived only after 10-15 minutes,after you died the first time.
So. You get shot at,"You are dead",5 minutes dead screen timer,friend revives you, you are shot again, This player has already been revived in the past 15 minutes,so he can't revive again.
Imagine how coll it will be,if they will add the drag person option.You are caught in a crossfire,the medic comes and drags you to safety,revives you and you are able to fight again.
Sorry if my english let's you down.
Good Luck and Have Fun survivors,hope you like my ideea :).