It isn't that the Sunsinger as an entire subclass is overpowered. It is more so that with a particular set up, which is run by literally every Sunsinger who hopes to be competitive. Firebolt Grenade, by itself is a pretty great grenade. With a 8m omnidirectional blast radius, three target caught within the blast are tracked by the Firebolt, and dealt 97 Damage. Touch of Flame provides all Grenades with a burning Damage over Time effect. This Dot ticks 5 times, dealing 7 damage per tick. Used in tandem with Firebolt, the initial Firebolt strikes for 97 damage, and an additional 35 Damage, for a total of 132 Damage. Viking Funeral, provide all DoT effects with an extension. The DoT for Touch of Flame is increase by 5 ticks, causing an additonal 35 damage, or as detailed "doubling the damage", for 167 damage. According to a few Destiny Guides, including the purchased guide at your local game store, without special equipment, the maximum health a guardian can have is 200, with Maximum Armour. Should a Warlock, who throws a Firebolt Grenade, catch an unfortunate Guardian within the large blast radius of their grenade, the target Guardian, should they be without a means of dodging, such as Shadowstep or Twilight Garrison, is Guaranteed to take 167 damage, with 33 Health remaining. At this point, anything in the Sunsinger's arsenal will kill the opposing Guardian, should the Warlock have landed at least two Assault Rifle Bullets, Two Pulse Rifle Bullets, a single Scout Rifle Bullet, Two Sidearm Bullets, a medium Ranged Shotgun Blast, their uncharged melee, and the list goes on. In addition, should a target be burning, with this setup, a Guardian's position is revealed to the Warlock for 10 seconds, providing not only a damage over time advantage, but also a strategic advantage for the Warlock, allowing for ambush, and cut off routes to be established, providing little, to no hope for most Guardians. Ironically, Thorn, a weapon much hated in year 1, was chastised for being too strong in its initial stages; however, Thorn in Year 1, dealt 86 damage for a critical, plus an additional 8 damage for 6 ticks, at a total of 156 damage. This was thought to be far too overpowered by every class, including Warlocks. The Particular setup for Warlocks actually deals far more damage than that of Thorn, and stands against the same arguments as the weapon. In reality, Warlocks do not want it nerfed, but fail to see that the numbers add up. Their ability is more powerful than that of a weapon, which has the same effects as their ability, which was nerfed for its sheer power. In the end, this combination is what needs the nerf, the Grenade has a blast radius that puts it on par with that of a rocket launcher, with abilities that put it on par with a year 1 Thorn. It is pretty OP.