Healing in cleric stance is such as waste, if you want to dps in the dungeon, why would you not pop out of cleric stance to heal then back in to dps? Your healing is much less potent in cleric stance so you will have to cast 2 or more heals to get the potency of 1 heal out of cleric stance...basically "lowering" your dps because you have to cast more heals.

Bind a hotkey already and just pop out and back in. You can't argue with numbers and no matter how you try to spin it, healing in cleric stance because you are too lazy to swap back is less dps than swapping and healing, then back to cleric stance for a nuke or two.