Kills are not the only thing that brings the satisfaction. Being a crucial part of the team is too. To be honest I think the main problem in playing medic is that it shines in team play and sucks in solo. One thing that could help is having two distinct cooldowns, one for heal self and another for heal other. A person with the ability to provide 100hp heals to two or three persons during a figth will be more then wanted in a group.
As it is now, shooters could have a basic medicine knowledge, but there is no need for someone with 200FA, 160 Doc and only 100-120 in SG i.e. apart from hardcore RP. And being a medic is boring because you can't actually be a medic. You are a one-use medpack.