WHM does go from being the worst dungeon healer to the best as it levels. WHM mana economy below 52 is terrible due to no Assize, Thin Air or 0 mp Lily heals, its GCD heals cost more than AST, it doesn't have an Embrace spamming fairy, it doesn't have Essential dignity or Lustrate on short cd. You don't even get Medica II until 50 or Tetra until 60. It's just Cure II's and Regen really. At 80 on the other hand it's a dungeon monster, massive burst aoe dps, stuns, plenty of healing.