I earn the most comms when I am a healer but I also get a decent amount as dps. I get the least amount when I am a tank regardless of how I did.

I had the commendation requirement finished months before I had 1000 dungeons complete so I am wondering why anyone would still not have enough of them by then?

I also have a similar system for handing out comms as people above but I do this because I do not like the vote or judge so it's the easiest way to spread them out equally.