Standings of Black Mage, Red Mage, and Summoner

[OcieKo]

In fact....Drain should be a BLM exclusive, with a bold potency enhancement, neither other caster needs it for a self heal. Pretty sure SMN Energy Drain is a better ability, could be wrong though

If were talking just for the heal Vercure > Drain > Energy Drain. Unless a Summoner needs the MP as well, using Energy Drain is worse than using Drain and Fester, Energy Drain's Aetherflow stack cost essentially brings it below Drain.