Personally, I run a Sunsinger as my main character. I have extensive experience with the subclass. In your post, you claim that sunsinger grenades are "fine." However, this is just not true. Sunsinger grenades are the most overpowered grenades in the game if the skill tree is used correctly. Viking Funeral and Touch of Flame paired with Firebolt grenades deals approximately 180 damage to a Guardian with 200 Health. Also, Sunsingers have the best melee in the game with Flame shield. Flame shield boasts the longest range in the game and is the only melee that will grant an overshield on HIT. Sunsinger needs to be nerfed in this regard. However, I agree with you 100% on the Song of Flame buff. I wouldn't mind if an exotic was released that granted Weapons of Light or Blessing of Light when you activate Song of Flame.