Radiance will make all the OTHER abilities you have selected when it is activated more powerful. Abilities in your build that do damage will do MORE damage. Abilities that reduce damage will reduce damage even further. It is a potentially more powerful Super than Nova Bomb...it is just more subtle. Because the more powerful you are as a character---and the more powerful your abilities are---the more impact activating Radiance will have. Making the Warlock potentially extremely dangerous...and not just dangerous with one ability or one damage class (Void damage) like the Nova Bomb/Golden Gun/FoH. Bungie didn't design ANY of its subclasses to fall neatly into the "Holy Trinity" of RPG games (Tank, DPS, Support/Healer). All of the subclasses are designed to be able to function in all three roles, so you are not rigidly limited in how you play and who you can play with. But in the SunSinger subclass, Fireborn has the possibility to be HUGE to a fireteam. Possibly being the difference between saving a Strike or Raid that is going badly....and having to start over.