The main things to look at are:
- Rate of healing
- Range of Heal
If the healing is fast medics will be 1:1 ratio and this is something that becomes annoying as you need more people to kill one person. This outcome, obviously, is not one that we would like to see happen. As everyone suddenly gets pocket medic and Juggs there way to victory.
If the range is too long then there is no downside for the 2 man team using the medic as he never needs to stick his head out and the other person is constantly getting a heal.
These points also apply to Armor repair. Well see how its balanced in beta though.