I know this would be an unpopular opinion, but I don't think an inventory-based job is the way to go for battles, especially for a healer. Does using potion actually have to be in the inventory, what happens then if you run out, let's say in the middle of an ultimate difficulty duty?

I think a mage-based healer would still better suit.

I like to have Geomancer in the game, whether it be a healer or a caster.