I'm a healer and i generally get 75k heals, 2.5k heal, and then sometimes when I'm running somewhere and i dont have the -30% heals debuff on me i will sacrifice my own health and get a 5k crit medal. So everygame i get at least 3, and then i will often get the killing blow medal plus the 10 enemies killed medal since i CC and throw dot's on people when everyone's health is ok, or when an objective is in trouble. So, i will get 5 medals a match if i am doing great, maybe 6 if i get to 300k healing, but that also depends on if the other team is doing that much damage to those around me. But the tank that puts guard on me gets almost that many just for standing close to me and enjoying my heals. Not that i don't appreciate him, but he gets 10-11 medals for the same amount of work i get for 5 medals.
Then again, i am consistently voted MVP so it might balance out.