I wanted it to be like the other guardians, but even they are each drastically different from each other. They each wield the light in a different way with a different body part. The Titans use their bodies' might to lay waste to any who stand in their way or shield their allies from harm, the hunters use their eyes and reflexes to make precision strikes at close range and deadly hits further away, and the Warlocks use their minds to bend the light to their wills to destroy and bolster their allies. So I thought what class archetype we needed next, and at first I thought we needed a healer, but I thought that was both too easy of a concept and too bland for Destiny, so I thought about the bards and how they use music to buff and heal and to attack, but of course we aren't carrying lutes into battle so I thought singing would be even better, the rest just kind of fell into place.

Warlocks are healers. Bathe sinsinger is heal and team buff and resurrection he's got the support side covered

Just checked the whole Sunsinger tree, and radiance doesn't heal, just reduces team ability cool downs and increases effectiveness, and they can only resurrect themselves with radiance