Medics will always be a fun topic.
Unless there is a decent incentive to play medic, I don't see how the mythical "Whitelisting" will solve anything.
Currently you either
1: Hang around Kavala to get revives
2: Spawn in Atheria and drive/fly around for 2 hours and get 1 revive seems 90% of people just respawn when your halfway there.
Surely we could setup medics like the "Drug Runner": You request your revive for $800. If you respawn after requesting a medic, have $2000 taken as a cancellation fee.
At least that way there's an incentive to only call a medic, when you're actually after a revive.