Someone presented the calculations. A RSII with Emp Healing hits for 560 HP with his Mass Heal. With 0 Healing amp on the target. That means, although Emp. Healing is the most SP-efficient metamagic for RSII, he will be most certainly overhealing the 600 HP targets (shouldn't let them drop to 40 HP, of course.) Now everybody with 600 HP should have healing amp (except WF arcanes, maybe). At least a 20% item. Ship buff maybe. Thats about 740 HP restored from one spell.
With these numbers, It's much easier and MUCH more spell efficient to heal a 800HP or 1000HP target than a 600HP target. This would save sp for a good divine, not make him use more pots .
The fact that many high HP people in endgame don't wear any healing amp doesn't mean we should introduce a divine spell for this. It rather means that they should learn to adjust their gear to the situation at hand .
Infant