Everything that shows additional information should not be implemented. Health bars are a problem.
First point: health bars last 3 seconds, so it lets the people know where you go, its like legal wallhacks.
Second point: health bars are still visible through grass, smoke, trees and walls, it doesnt dissappear. Still a problem.
Third point: health bars gives you information of a potential 3rd party chance with only 1 shot, instead of thinking: is it worth to rush this to get better position or should we rotate? Instead of just no brain rushing because one of them is low health.
Fourth point: there was a skill not to many people recognize but that got lost: calling the damage numbers and calculating how much health one enemy had. That skill is lost now because everyone just see the health bar and know how much dmg one person has.
Health bar is not a good addition. Maybe for gamemodes, but for pubs or ranked is not good.