No, no you do not want to blow Assize on cooldown. That mentality made healing Exdeath much harder as I simply didn't have enough options between the Stack, Flares and White Hole. You typically want to time Assize for large AoE bursts yet not sit on it too long. As for throwing a Cure or Cure II on the tank, that's a DPS loss if HoTs would have ticked them up otherwise. Lilies work for dungeons or if you have enough fluff damage going out to compensate for utilizing Cure II more. It's rarely ever something you plan consistency but sort of happens. Hence why people have such a dislike towards Lilies.