TL;DR
But what ever,
It's a big risk to heal a knockout teammate, you are risking:
1. Getting knockedout.
2. Rocket explosive radius.
3. Weapon splash from enemy.
A perk to have ability to do something that even in 20v20 battles on other server is rarely being used (When it's free!) is a waste. However I do not like the idea of another perk which isn't being taken anymore. Perhaps give it a flat +35hp when healing on teammates along with KO-Recovery ability.