So hear me out. Splash of light is a quite powerful heal for groups but nothin for war or OPR. My recommendation is this and i feel it would completely balance it, and all healers a alternative and the ability to heal themselves while also healing allies.
1st; change the spell to instead of all group members within 100m to up to 5+healer within 25m.
2nd; to prevent abuse and spamming, have when someone has been healed by splash of light have a light sickness preventing them from being healed again from splash of light for 20sec.
3rd; allow the debuff perk to remove 1 debuff on 7 targets to make it more appealing if you mess up on timers.