Not too sure, I have very few runs when I don't get more than 1 commendation and most times I DF as DPS. I go into expert with summoner almost guaranties 2 commendations, sometimes 3. Maybe it's not about role and more about people actually giving the commendation to the players they think deserve it (Working as intended)? Although there are plenty times I go as scholar and walk out with 3. I don't given commendations unless I'm impressed with a player. And you can be be sure that who ever got it probably got at least one other player's commendation as well. People saying that mostly healers and tanks get commendations are simply not getting them because they probably haven't impressed anyone. BTW, I don't chat in dungeons so I don't say "Hello" at the beginning or try to be friendly. I just do my job.