Why people have such a fuss over the perk I will never know :? But what ever you decide, please do not change the revive time, making it so you can only be revived once. That takes away the "Medic" ability that I love most, or what makes it special!! Its like you stated:
It's a "perk". Look up what perk means. It needs to offer something.
"You cant win them all" Every now and then your going to get killed by it. (Thats the whole point; getting a 2nd chance to fight back ;)
In a sick way, 2nd chance is insurance against one hit kill weapons. It also rewards teamwork.