I've always been partial to tank and dps, two low maintenance roles in a traditional party. Back when I played Everquest live in 2000 I had a Paladin and a Monk I'd trade off on back and forth. Though I never got to do raids it was still fun to do small pick up groups in dungeons like Crushbone or Blackburrow where I tanked on the Paladin or did assist dps on the Monk.
Healing in mmos always felt daunting to me because of the responsibility of keeping the party alive in tight situations. But I can see how it would be fun when you get into a rhythm of playing.