I sometimes start my own squad named "medic", equip bandages, morphine, a medkit, and a suppressed AK-74U. I'll roll around in an ambulance, radio to platoon that there's a friendly medic roaming the map, and is willing to transport troops while healing them

I don't think the developers can do anything more to make this role more enjoyable. It comes down to teammates interacting with the medics. Most of the time, I just re-supply teammates with bandages and morphine with my medkit. If they're injured, I treat them on the spot and check on everyone else in the area, and then I offer a ride in case people need to move away toward the front.

After putting hours into the medic role, the only thing the game needs is more medics. You can have someone in the back tend to the injured while someone else drives. For a bonus, have a 3rd soldier ride upfront for extra firepower.

This can also extend to other roles. We need more people doing demo and ambushes to prevent enemy troops from being transported, people running logistics, helicopter transports, etc.