In Divinity 1, Source magic was exclusively associated with the healing spring. I think Divinity 2 : Flames of Vengeance also had a passing mention of a healing spring in Source Square that the healers couldn't reach.
Therefore, some kind of healing, possibly associated with the water element should be in the game. Maybe a moderate-to-high level "Healing Rain" spell which is great for healing you... but it also heals everything else around you too. (I think healing does not damage undead in the Divinity series, so this would also heal undead.)
