If something like this were to be added, wouldn't it nearly remove the purpose of having medics? Just like how some argue to have fire extinguishers put into police vehicles and ambulances, which in turn would also reduce the purpose of having firefighters. So essentially we would just boil it down to having police as the one and only job, the variety of having jobs is what helps lead to RP. Roleplay at its heart requires lots of peoples that fill all sorts of roles which that player may find more exciting than another, and therefore create a type of world in which people live. Creating this world is not always easy as each job is not hugely exciting or worthwhile. People tend to like being police as you might get an opportunity to shoot someone, which to many is quite a lot of fun, medics and firefighters however, don't get to do much but the small menial tasks that are important but no one likes doing. Drugs pay out the best (naturally) but do nothing to help advance society so to others money is a plain and simple motivator of what they want to do.
Anyhow back to the point, I see this addition taking away from what medics are tasked to do. I gave firefighters the ability to heal players as it leaves reviving (and recently, helping to identify killers with the DNA sampler tool) to medics. So if I'm going to add something such as CPR, I see no purpose in keeping the medic job around. However with no medics, to me it removes some of the RP experience, since they are an integral part of the community.
On to my solution of how this could work actually. I could see this as someone said taking stamina to help support someone that is dying away, however since the death timer is 5 minutes (too long *grumble grumble* for some) and people will die off in 4 (unable to be revived) the death timer would need be increased (this could be only if there are medics on duty). And I highly doubt many people really would want to be dead for longer, however, it helps promote a way to having to avoid worrying about NLR, and gives incentive to be careful with your character's life.
Quick note, some think firefighters/police would be able to perform first aid, while this is true, when you're reviving someone, you're doing far more than patching wounds or sewing stitches, you are saving their life by restarting their heart (hence the defibs).
