The problem is that Sunbreaker is considerably more vulnerable from focused fire than it used to be. Bungie really only needed to nerf either damage resistance, Cauterize, or Hammer effectiveness, not all three. Sunbreaker is too dependent on Cauterize to take on a group, and that doesn't even address the chances of getting head shot from a sniper is very high these days. The biggest change I made was be much more cautious in my approach and not rush every engagement. It's still a very strong subclass imo.