No healing beams or bubbles, ever. Without them, you can sometimes win even at a numerical disadvantage via better aim, evasion, and tactics. Once the enemy has a brainless spam healer hiding in a corner, everyone on their team effectively has more health, and it's pretty much impossible to beat. Combat becomes less skillful and more mathematical. Please don't doom your game to mediocrity like so many other "fast-paced, skill-based" games by adding healers. They turn good shooter gameplay into mediocre MMO gameplay.