To be honest I feel that this game over compensates tanks and healers for a lot of the raids in this game. I think it would help new healers learn how to heal in a raid setting if there wasn't always a 2nd healer covering up their mistakes (because if this game really needed 2 healers you would wipe due to lack of hps if one healer slacked off). I think that's why you see a lot of the healer dps rants on the forums for the most part.

What would make healing more fun is if they actually reduced the number of healers and tanks per raid to only 1 and only getting more when it's necessary to that particular fight. For example Titan Hard mode only needs 1 tank, but Titan extreme needs 2 and the DF should recruit accordingly. This game feels perfectly balanced for one healer because even when a healer is completely new to a dungeon/trial I always let them solo heal and most of the time they do just fine without even realizing they just solo healed while I go full time dps.