In games, the point of burns or poisons(Dots) is to DO MORE DAMAGE over a LONG PERIOD OF TIME. The time is important because Dots are for long term fights or when up against a horde of low tier enemies. In Destiny, Dots neither last long enough or do enough damage to have a meaningful use because PvP balance issues. What should have happened with the Thorn in PvE is you take 1 shot per low tier enemy and watch them all burn to death. Same with Firebolts. Destiny 2 must separate PvP and PvE balance