Quote Originally Posted by Shurrikhan View Post
Take a look at the Mistwalker Monk healer. Apart from one minor CD, Mana Tea, its mana recovery IS melee DPS. Holy Priest healing partly benefits burst damage as well. In WoD, Holy Paladin's filler damage also prevented targets from critting. Since Vanilla, its damaging debuffs supplied raid healing. Healer design has always had some expectation that direct damage will outweigh healing for certain globals.
Healers never did damage for the sake of damage in WoW, only because something else was attached to it. The debuff part is the sole reason for damage skill usage in your "damaging debuffs". Healer damage was also on par with what FFXIV healers do now without Cleric. Somewhat high mana costs combined with the 5-second rule really put a hold on any dreams about damage, and accuracy and partial to full resists were also problems.

I'm pretty sure Seal of Light didn't even do any damage when judged back in vanilla, or if it did, it was in the low hundreds, meaning it didn't even register in the 40-man raids. Debuff caps in the beginning and it healing for something like 20-30 per melee hit meant it was used maybe once a year. I think it even had something like 40 charges shared with everyone.